Marshmallow Brownies

Imagine pulling a pan of marshmallow brownies from the oven — the aroma of rich chocolate filling your kitchen, ribbons of golden marshmallow creme swirled into a glossy, fudgy top. These aren’t your average brownies. They combine a deeply chocolatey, chewy base with pillowy marshmallow swirls that create something truly irresistible. Marshmallow brownies are special because they deliver two textures in every bite: dense, fudgy brownie and soft, creamy marshmallow. You’ll learn how to make them from scratch, how to nail the swirl technique, and how to store and serve them perfectly.

Why You’ll Love This Recipe

These marshmallow brownies check every box you could want in a dessert. First, the texture is extraordinary — deeply fudgy, chewy, and rich thanks to a combination of melted butter, oil, and dutch process cocoa powder that delivers intense chocolate flavor. The marshmallow creme swirled on top adds a dreamy, pillowy contrast that makes every single bite feel like an indulgence.

Second, the recipe is surprisingly straightforward. You don’t need any special baking skills. A hand or stand mixer, a 9×9-inch pan, and a few pantry staples are all it takes. The steps are clear and manageable even for beginner bakers.

Third, these brownies are a genuine crowd-pleaser. Whether you’re baking for a party, a bake sale, or simply a weekend treat, they consistently impress. The swirled marshmallow topping makes them look stunning without requiring any decorating expertise. Once you try these marshmallow fudge brownies, you’ll return to this recipe again and again.

Ingredients List for the Marshmallow Brownies

These marshmallow brownies use simple, accessible ingredients that come together beautifully. Measure everything before you begin for a smooth, stress-free baking experience.

• 2 cups white granulated sugar

• 3 large eggs

• 1 egg yolk

• 1/2 cup unsalted butter (melted)

• 2 tsp pure vanilla extract

• 1/2 cup oil (canola or vegetable)

• 3/4 cup all-purpose flour

• 1 cup unsweetened cocoa powder (use dutch process cocoa powder)

• 1 1/2 TBSP cornstarch

• 1/2 tsp salt

• 1 cup semi-sweet chocolate chips

• 1 cup marshmallow creme

Pro Tips

Getting marshmallow brownies right comes down to a few key techniques that make a significant difference in the final result.

Whip the sugar and eggs thoroughly. Beating the sugar, eggs, and egg yolk on high speed for a full five minutes is non-negotiable. This step incorporates air into the batter, creates a shiny, crackly top, and gives the brownies their signature chewy texture. Don’t cut this step short.

Don’t overbake. The most common brownie mistake is baking too long. These brownies are done when a toothpick inserted into the center comes out slightly wet — not clean. Overbaking will dry them out and destroy that fudgy center you’re working toward.

Warm the marshmallow creme before swirling. Microwaving the marshmallow creme for 20-30 seconds makes it fluid enough to dollop and swirl easily. If it’s too thick and cold, you’ll tear the batter instead of creating those beautiful swirls. Use a light hand with the butter knife for the best visual result.

Instructions

Step 1:
Preheat the oven to 325°F. Spray a 9×9-inch baking pan with baking nonstick spray. Line the bottom and 2 sides of the pan with parchment paper and spray again.

Step 2:
In a medium bowl, sift the flour, cocoa powder, and cornstarch together. Add in the salt and set aside.

Step 3:
Using a mixer with a whisk attachment, beat the sugar, eggs, and egg yolk on high speed for 5 minutes. It will become pale in color. While that mixes, melt the butter in the microwave and let it cool.

Step 4:
Add the oil, melted butter, and vanilla and mix on low until combined. Add in the dry ingredients and mix on low until just combined. Pour in the chocolate chips and use a rubber spatula to fold it in.

Step 5:
Pour the brownie batter into the pan. Melt the marshmallow fluff in the microwave for 20-30 seconds and mix. Use a 1 teaspoon to dollop the marshmallow fluff on top of the brownie batter. Use a butter knife to very lightly swirl the marshmallow fluff.

Step 6:
Bake for 45-55 minutes. It is done baking when you stick in a toothpick, and it is slightly wet. If a lot of batter comes out, then bake for another 5 minutes.

Step 7:
Cool on a cooling rack completely before cutting into them and serving.

Variations

These marshmallow swirl brownies are wonderfully versatile. Here are a few popular ways to switch things up:

Rocky Road Brownies: Add 1/2 cup of chopped roasted almonds and 1/2 cup of mini marshmallows directly into the batter along with the chocolate chips. The nuts add crunch and a classic rocky road flavor profile that pairs beautifully with the fudgy base.

Peanut Butter Marshmallow Brownies: Drop small spoonfuls of creamy peanut butter alongside the marshmallow creme before swirling. The combination of chocolate, peanut butter, and marshmallow is an absolute flavor triumph that chocolate and peanut butter lovers will adore.

Dark Chocolate Marshmallow Brownies: Swap the semi-sweet chocolate chips for dark chocolate chips and use extra-dark dutch process cocoa powder. This version delivers a more intense, bittersweet chocolate flavor that balances the sweetness of the marshmallow creme perfectly.

Storage and Serving

Storing your brownies: Once completely cooled, store marshmallow brownies in an airtight container at room temperature for up to 4 days. Place a sheet of parchment paper between layers to prevent sticking. For longer storage, wrap individual brownies tightly in plastic wrap and freeze them for up to 2 months. Thaw at room temperature before serving.

Serving suggestions: These brownies are delicious on their own, but a few simple additions take them to the next level. Serve warm with a scoop of vanilla ice cream for an indulgent dessert. A drizzle of hot fudge or caramel sauce over the top adds extra richness. For parties, cut them into smaller bite-sized squares and arrange them on a platter for an impressive and easy-to-share presentation that guests will love.

FAQs

Can I use a 9×13-inch pan instead of a 9×9-inch pan?
Yes, but the batter will spread thinner, so reduce the baking time. Start checking for doneness around 30-35 minutes using the toothpick test.

Can I use regular cocoa powder instead of dutch process?
You can, but dutch process cocoa powder delivers a smoother, richer, less acidic chocolate flavor that is strongly recommended for this recipe. The results will differ slightly with natural cocoa powder.

Why do my brownies need to cool completely before cutting?
Cutting warm brownies causes them to crumble and fall apart. Cooling allows the structure to fully set, giving you clean, beautiful slices with defined layers of brownie and marshmallow.

Can I use mini marshmallows instead of marshmallow creme?
Marshmallow creme is specifically recommended for this recipe because it swirls smoothly into the batter. Mini marshmallows behave differently during baking and will not produce the same result.

How do I know when the brownies are perfectly baked?
Insert a toothpick into the center of the pan. If it comes out slightly wet with a few moist crumbs, the brownies are done. A clean toothpick means they are overbaked and may be dry.

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