Irresistibly Fudgy Marshmallow Swirl Brownies: Your Ultimate Chocolate Dream

Prepare to be enchanted by these irresistibly fudgy marshmallow swirl brownies, a decadent creation that marries the intense richness of a chocolate brownie with the sweet, gooey embrace of marshmallow fluff. Each square promises an ultra-fudgy texture, generously studded with premium chocolate chips, and crowned with elegant swirls of fluffy marshmallow, baked right into the batter. This isn’t just a dessert; it’s a celebration of chocolate and a dream come true for anyone who loves rich, comforting treats with a delightful twist. Perfect for any occasion, from cozy nights in to festive gatherings, these brownies are guaranteed to be a showstopper.

Imagine the beloved flavors of s’mores transformed into a convenient, crave-worthy brownie. These gooey marshmallow brownies deliver that classic campfire experience but without the graham crackers, letting the rich chocolate and airy marshmallow take center stage. They boast an incredibly soft, moist crumb with pockets of melted chocolate, all uplifted by that signature marshmallow fluff swirl that caramelizes ever so slightly as it bakes. The result is a dessert that’s both elegant and utterly satisfying, a true testament to the magic that happens when chocolate meets marshmallow.

While these fudgy brownies are undeniably rich and sweet on their own, their indulgence reaches new heights when paired. Serve them alongside a frosty glass of cold milk to cut through the richness, or elevate the experience with a scoop of creamy vanilla ice cream. The contrast of warm brownie against cold ice cream, combined with the varying textures, creates a symphony of flavors and sensations that makes these brownies truly perfect. They are more than just a dessert; they are an experience waiting to be savored.

If you’re as passionate about marshmallows as we are, you’ll love exploring more of our delightful recipes. Expand your sweet repertoire with our Chocolate Chip Marshmallow Cookies, a chewy classic with pockets of melted marshmallow, or dive into the deep cocoa flavor of our Chocolate Marshmallow Cookies. For a nostalgic treat with a twist, don’t miss our Chocolate Rice Krispie Treats, offering another unique way to enjoy that beloved sticky-sweet ingredient.

Why These Marshmallow Swirl Brownies Are a Must-Try

These aren’t just any brownies; they’re meticulously crafted to deliver an unforgettable dessert experience. Here’s why this marshmallow brownie recipe stands out and earns its place as a staple in your baking repertoire:

• Unmatched Fudgy Texture: What truly sets these brownies apart is their luxurious fudgy texture. This isn’t a cakey brownie; it’s dense, moist, and chewy, melting in your mouth with every bite. The secret lies in a carefully balanced ratio of fat to flour, including an extra egg yolk, which adds richness and acts as an emulsifier, contributing to that desirable moist, chewy consistency. We’ve also incorporated a touch of cornstarch, a clever ingredient that helps inhibit gluten development, ensuring your brownies stay incredibly tender and perfectly fudgy, never dry or crumbly. This foundational brownie recipe is so reliable, it’s based on our highly acclaimed Better Than Boxed Brownies, guaranteeing consistent perfection.
• Rich, Intense Chocolate Flavor: For true chocolate enthusiasts, these brownies are a dream. We don’t just use one form of chocolate; we double down to maximize the flavor experience. Unsweetened cocoa powder provides a deep, complex chocolate base, giving the brownies their intense color and robust flavor. Complementing this, generous amounts of high-quality chocolate chips are folded into the batter, ensuring pockets of melted, gooey chocolate throughout. This combination delivers a multi-layered chocolate experience that’s both profound and satisfying, making every bite a decadent pleasure.
• Dreamy Marshmallow Swirl: The addition of marshmallow fluff is the whimsical touch that elevates these brownies from great to extraordinary. Swirled directly into the brownie batter before baking, the marshmallow fluff transforms, creating pockets of fluffy, melt-in-your-mouth sweetness that perfectly contrasts with the rich chocolate. This creates a beautiful visual marble effect and adds a wonderfully chewy, slightly caramelized top that makes each brownie uniquely delightful. It’s the perfect balance of classic brownie comfort and a playful, sweet surprise.
• A Chocolate Lover’s Paradise: If your heart beats for chocolate, these brownies are crafted with you in mind. From the intense cocoa foundation to the generous scattering of chocolate chips and the sweet marshmallow swirls, every element is designed to amplify the chocolate experience. This recipe is a celebration of chocolate in all its glory, offering a dessert that is deeply satisfying, wonderfully textured, and utterly indulgent. Prepare to fall in love with these brownies!

Essential Ingredients for Perfect Marshmallow Brownies

Crafting the perfect marshmallow swirl brownie begins with understanding the role of each ingredient. Here are some detailed notes to ensure you get the best results:

• Eggs & Egg Yolk: We use three large eggs and an additional egg yolk, all taken straight from the fridge. The cold temperature of the eggs, combined with vigorous whipping with sugar, is key to achieving that desirable crackly top and light, airy structure. The extra egg yolk plays a crucial role in enhancing the fudgy texture, adding richness and moisture without making the brownies cakey.
• Unsalted Butter: Melted unsalted butter is essential for these brownies. Ensure it’s melted completely but then cooled to room temperature before incorporating it into the batter. This prevents it from scrambling the eggs and helps maintain the fudgy consistency. Unsalted butter allows you to control the overall salt content of your brownies.
• Oil: The addition of oil, such as canola, vegetable, or a light olive oil, contributes significantly to the brownies’ ultimate fudginess and moisture. Oil stays liquid at room temperature, unlike butter which solidifies, helping the brownies stay moist and chewy for days. Choose a neutral-flavored oil to let the chocolate shine.
• Unsweetened Cocoa Powder: For the most rich, dark, and intense chocolate flavor, we highly recommend using Dutch-process cocoa powder. This type of cocoa has been alkalized, reducing its acidity and resulting in a smoother, less bitter, and deeper chocolate taste and color. This is the Dutch-process cocoa powder I typically use for unparalleled results.
• Cornstarch: This seemingly minor ingredient is a secret weapon for achieving truly fudgy brownies. Cornstarch helps to tenderize the gluten in the flour, preventing the brownies from becoming tough or overly cakey. It contributes to that dense, moist, and wonderfully chewy texture we all crave in a perfect brownie.
• Chocolate Chips: For this recipe, semi-sweet chocolate chips or dark chocolate chips are ideal. Their balanced sweetness complements the richness of the cocoa powder beautifully. We advise against using milk chocolate chips as they can make the brownies excessively sweet, overpowering the complex chocolate flavor profile.
• Marshmallow Crème or Marshmallow Fluff: These two terms are often used interchangeably, and both work perfectly for this recipe. Whether you call it crème or fluff, ensure you have a good quality, sticky marshmallow spread. It will be gently melted and swirled into the batter, creating those irresistible pockets of sweet, chewy marshmallow.

Dietary Adjustments: Ingredient Substitutions

We understand that dietary needs vary. While this recipe is designed with classic ingredients, here are some potential substitutions:

• Dairy-Free: To make these brownies dairy-free, you can easily substitute the unsalted butter with your favorite plant-based butter (stick form works best) and ensure your chocolate chips are certified dairy-free. Most oils (canola, vegetable) are already dairy-free, as is marshmallow fluff, but always double-check labels to be certain.
• Gluten-Free: We haven’t extensively tested this particular recipe with gluten-free flour. However, many bakers have success substituting all-purpose flour with a 1:1 gluten-free baking blend that contains xanthan gum. If you decide to try a gluten-free version, we’d love to hear about your results!

Step-by-Step Guide to Baking Fudgy Marshmallow Brownies

Get ready to bake the most incredible fudgy marshmallow swirl brownies! This recipe is straightforward, but attention to detail ensures perfect results. You’ll need a 9×9-inch square baking pan, a stand mixer with a whisk attachment (or a reliable electric hand mixer), and a rubber spatula for folding.

1. Prepare Your Pan and Dry Ingredients: Begin by preheating your oven to 325°F (160°C). Prepare your 9×9-inch baking pan by spraying it thoroughly with nonstick baking spray. To ensure easy removal, line the bottom and two sides of the pan with parchment paper, leaving a slight overhang that will act as “handles.” Spray the parchment paper again. In a separate medium bowl, use a sifter to combine the all-purpose flour, unsweetened cocoa powder, and cornstarch. Sifting ensures a lump-free, evenly mixed batter. Stir in the salt and set this dry mixture aside.
2. Whip Eggs and Sugar to Perfection: In a large mixing bowl, combine the granulated sugar, large eggs, and the extra egg yolk. Using your electric mixer with the whisk attachment, beat these ingredients on high speed for a full 5 minutes. Initially, the mixture will be yellow, but as you whip it, it will transform into a pale, thick, and fluffy consistency. This crucial step incorporates air, which is essential for developing the brownies’ signature crackle top and aiding in their rise during baking. While this is whipping, melt your unsalted butter in the microwave and set it aside to cool slightly.
3. Incorporate Wet Ingredients: Once the egg and sugar mixture is light and pale, reduce your mixer speed to low. Add the cooled melted butter, the oil (canola or vegetable), and the pure vanilla extract. Mix gently until all the wet ingredients are just combined. Avoid overmixing at this stage to keep the batter tender.
4. Combine & Fold in Chocolate Chips: With the mixer still on low speed, gradually add the reserved dry flour mixture to the wet ingredients. Mix until just combined, stopping as soon as no dry streaks of flour are visible. Overmixing the flour can develop too much gluten, resulting in a tougher, cakey brownie. Finally, remove the bowl from the mixer and use a rubber spatula to gently fold in the semi-sweet chocolate chips, distributing them evenly throughout the batter.

5. Create the Marshmallow Swirl: Pour the luscious brownie batter into your prepared baking pan, spreading it evenly with your rubber spatula. For the marshmallow swirl, lightly warm the marshmallow fluff in the microwave for 20-30 seconds until it’s slightly more fluid and easier to work with. Stir it well. Using a teaspoon, dollop small amounts of the warmed marshmallow fluff randomly over the top of the brownie batter. Then, take a butter knife or a thin skewer and gently swirl the marshmallow into the chocolate batter to create beautiful ribbons and pockets of sweet fluff. Be careful not to overmix the swirl; a light hand will yield the best marble effect.

6. Bake to Fudgy Perfection & Cool: Place the pan in your preheated oven and bake for 45-55 minutes. Brownies are famously best when slightly underbaked. To check for doneness, insert a toothpick into the center of the brownies. It should come out with moist crumbs attached, but not wet batter. If a lot of wet batter comes out, bake for another 5 minutes, then re-test. Remember, brownies continue to cook from residual heat as they cool, so slightly underbaking ensures that ultimate fudgy center. Once baked, remove the pan from the oven and transfer it to a wire cooling rack. Allow the gooey chocolate brownies to cool completely in the pan before attempting to cut them. This is a crucial step for achieving clean slices and preserving their fudgy texture.

Pro Baking Tips for the Best Brownies

Achieving bakery-quality brownies at home is easier than you think with these expert tips:

• Measure Flour Accurately: Precision in flour measurement is paramount. Always spoon your all-purpose flour into the measuring cup and then level it off with a straight edge. Never scoop the measuring cup directly into the flour bag, as this can compact the flour, leading to an excess amount. Too much flour will result in dry, cakey brownies, detracting from the desired fudgy texture.
• Don’t Overbake: This is arguably the most critical tip for fudgy brownies. The key is to remove them from the oven when they are just slightly underdone. A toothpick inserted into the center should come out with moist crumbs, not liquid batter. If the toothpick is completely clean, your brownies might already be overbaked. Brownies continue to cook and set as they cool, so a slight jiggly center will firm up to perfect fudginess. Overbaked brownies will lose their signature chewy, dense texture and become dry.
• Easy Removal from the Pan: To effortlessly remove your baked brownies, start by generously spraying your baking pan with a good quality nonstick baking spray. Then, line the bottom and two opposing sides of the pan with parchment paper, allowing the paper to overhang. This creates convenient “handles.” Spray the parchment paper again. Once the brownies have completely cooled, simply use these parchment paper handles to lift the entire slab out of the pan, making cutting a breeze.
• Perfectly Clean Cuts: For professional-looking brownie squares, chill your brownies in the freezer for about 10-15 minutes before cutting. This firms them up, preventing crumbling and sticking. Use a large, sharp knife, and after each cut, wipe the blade clean with a damp cloth or paper towel. This ensures each slice is neat and tidy, showcasing the beautiful fudgy interior and marshmallow swirl.

Frequently Asked Questions (FAQ)

Exciting Recipe Variations to Try

While these marshmallow swirl brownies are perfect as is, they also serve as a fantastic canvas for your culinary creativity:

• Toasted Marshmallow Topping: Instead of swirling the marshmallow fluff into the batter before baking, you can bake the brownies plain. Once they are almost done or fully cooled, spread a layer of marshmallow fluff over the top and briefly broil them in the oven until the marshmallow is beautifully golden brown and lightly toasted. Keep a close eye on them, as marshmallow can burn quickly!
• Nutty Crunch: For added texture and flavor, fold in 1/2 cup of chopped nuts like walnuts, pecans, or almonds along with the chocolate chips.
• Espresso Kick: Enhance the chocolate flavor by adding 1-2 teaspoons of instant espresso powder or coffee granules to your dry ingredients. It won’t make the brownies taste like coffee, but it will deepen and intensify the chocolate.
• Different Chocolate Chips: Experiment with white chocolate chips, butterscotch chips, or a mix of dark and milk chocolate chips for varying flavor profiles.

Recommended Tools for Brownie Baking

Having the right tools can make your baking experience much smoother and more enjoyable:

• 9×9 Inch Metal Baking Pan: We strongly recommend using a metal square baking pan for this recipe. Metal pans conduct heat more efficiently and evenly than glass pans, leading to a better rise and a more consistent bake with perfectly crisp edges and a fudgy center. Glass pans tend to heat slower and retain heat longer, which can sometimes result in overbaked edges and a less even cook.
• Parchment Paper Sheets: Investing in pre-cut sheets of parchment paper can be a game-changer. They lie flat without curling, making pan preparation significantly easier and saving you time and frustration compared to rolls of parchment paper. They are essential for easy brownie removal.
• Non-Stick Baking Spray with Flour: For ultimate non-stick assurance, use a baking spray that contains flour. This dual-action spray creates an effective barrier, ensuring your brownies release cleanly from the pan every single time, especially important for fudgy recipes.
• Offset Spatula: An offset spatula is an invaluable tool for evenly spreading thick batters like brownie batter into the pan. Its angled blade allows you to smooth the surface without disturbing the edges, ensuring a consistent thickness for even baking.

Storing and Freezing Your Marshmallow Brownies

Proper storage is key to keeping your fudgy marshmallow brownies fresh and delicious for as long as possible:

Store the baked and completely cooled marshmallow brownies in an airtight container at room temperature. They will retain their incredible fudgy texture and flavor for up to 5 days. For an extra indulgent treat, you can heat individual brownies in the microwave for 10-15 seconds until just warm and serve them with a scoop of vanilla ice cream.

Freezing for Later Enjoyment

These brownies are excellent for freezing! To freeze, allow them to cool completely, then cut them into individual squares. Wrap each square tightly in plastic wrap, then place the wrapped brownies in an airtight freezer-safe container or a heavy-duty freezer bag. They can be frozen for up to 30 days without losing quality.

To thaw, simply take the desired number of frozen brownies out of the freezer. You can either let them come to room temperature on your countertop for about an hour or warm them gently in the microwave for 30-60 seconds until they are soft and warm. They’ll be just as delicious as when they were first baked!

More Delicious Recipes You’ll Love

Other Brownie Recipes To Indulge In

If you’re a brownie aficionado, you’ll love exploring these other delightful variations from our collection. Each offers a unique twist on the classic fudgy treat:

• Classic Fudge Brownies: Master the art of the perfect fudgy brownie with our foundational recipe.
• Peanut Butter Swirl Brownies: A harmonious blend of rich chocolate and creamy peanut butter in every bite.

Delightful Marshmallow Creations

Beyond brownies, the magic of marshmallows transforms many desserts. Here are more recipes featuring this beloved ingredient:

• Chocolate Marshmallow Cookies
• Chocolate Chip Marshmallow Cookies
• S’mores Cake
• S’mores Cookies

Recipe Card: Fudgy Marshmallow Swirl Brownies

Marshmallow Brownies

Author: Stephanie Rutherford

Summary: These marshmallow brownies are incredibly fudgy chocolate brownies packed with chocolate chips, featuring a delightful marshmallow fluff swirl on top. A truly irresistible treat for any chocolate and marshmallow lover!

Prep Time: 15 minutes

Cook Time: 50 minutes

Total Time: 1 hour 5 minutes

Servings: 16 brownies

Ingredients

• 2 cups White granulated sugar
• 3 Large eggs
• 1 Egg yolk
• 1/2 cup Unsalted butter, melted and cooled
• 2 tsp Pure vanilla extract
• 1/2 cup Oil (canola or vegetable)
• 3/4 cup All-purpose flour
• 1 cup Unsweetened cocoa powder (Dutch-process recommended for rich flavor)
• 1 1/2 TBSP Cornstarch
• 1/2 tsp Salt
• 1 cup Semi-sweet chocolate chips (or dark chocolate chips)
• 1 cup Marshmallow creme or marshmallow fluff

Instructions

1. Preheat your oven to 325°F (160°C). Prepare a 9×9-inch baking pan by spraying it generously with nonstick baking spray. Line the bottom and two sides of the pan with parchment paper, leaving an overhang to create “handles” for easy removal. Spray the parchment paper again.
2. In a medium bowl, sift together the all-purpose flour, unsweetened cocoa powder, and cornstarch. Add the salt and whisk to combine thoroughly. Set this dry mixture aside.
3. In a large bowl, using an electric mixer fitted with a whisk attachment (or a hand mixer), beat the granulated sugar, large eggs, and the extra egg yolk on high speed for about 5 minutes. The mixture will lighten in color and become thick and pale yellow, almost white. While this is mixing, melt the unsalted butter in the microwave and allow it to cool slightly.
4. Reduce the mixer speed to low. Carefully add the cooled melted butter, oil (canola or vegetable), and pure vanilla extract to the egg-sugar mixture. Mix until just combined, being careful not to overmix. Gradually add the reserved dry ingredient mixture to the wet ingredients, mixing on low speed until just combined. Stop mixing as soon as no dry streaks remain. Gently fold in the semi-sweet chocolate chips with a rubber spatula.
5. Pour the rich brownie batter evenly into your prepared 9×9-inch baking pan. For the marshmallow swirl, microwave the marshmallow creme (or fluff) for 20-30 seconds until it’s slightly warmed and more fluid, then stir it. Using a teaspoon, dollop spoonfuls of the melted marshmallow fluff over the top of the brownie batter. Take a butter knife or a skewer and gently swirl the marshmallow into the brownie batter for a beautiful marble effect.
6. Bake for 45-55 minutes. To test for doneness, insert a toothpick into the center of the brownies. It should come out with moist crumbs attached, indicating they are slightly underbaked – this is the secret to ultimate fudginess. If it comes out with a lot of wet batter, bake for an additional 5 minutes, then re-test.
7. Once baked, transfer the pan to a wire cooling rack and allow the brownies to cool completely before attempting to cut and serve. Patience is key for perfectly set, fudgy brownies!

Nutrition Information (per serving)

• Calories: 336 kcal
• Carbohydrates: 46g
• Protein: 2g
• Fat: 18g
• Saturated Fat: 7g
• Polyunsaturated Fat: 2g
• Monounsaturated Fat: 7g
• Trans Fat: 0.3g
• Cholesterol: 16mg
• Sodium: 76mg
• Potassium: 155mg
• Fiber: 3g
• Sugar: 34g
• Vitamin A: 183 IU
• Calcium: 17mg
• Iron: 2mg

If you tried and loved this recipe, we’d be thrilled to hear from you! Please consider sharing your experience. Don’t forget to tag us on Instagram @stephaniesweettreats with your creations. For more sweet ideas and inspiration, be sure to follow us on Pinterest.