Marshmallow Brownies

These fudgy marshmallow brownies feature a rich, crackly chocolate base topped with gooey, toasted marshmallows and a glossy chocolate drizzle.

Why This Recipe Works:

• The two-stage baking method prevents the marshmallows from dissolving into the batter.
• Using Dutch-processed cocoa powder ensures a deep, fudgy chocolate flavor that balances the sweet topping.
• A touch of oil alongside butter keeps the crumb incredibly moist, even after a day in the fridge.

I still remember the rainy Tuesday in October when I tried to make these for my sister's bake sale and ended up with a smoking, carbonized sheet pan. My kitchen smelled like a campfire gone wrong, and my forearms ached from scrubbing the burnt sugar off my favorite Nordic Ware pan.

Marshmallows are notoriously chaotic in the oven.

If you toss them onto the batter too early, the high water content in the marshmallows destabilizes the batter's protein matrix. Bear with me here, think about this in terms of physics: the steam escaping the baking brownie literally dissolves the gelatin structure from the inside out.

The simple fix is a two-stage bake where we let the brownies set completely before adding the marshmallows for a quick, high-heat broil. I tested this with six different brands of marshmallows, and the cheap store-brand ones actually held their shape better than the artisanal, hand-cut varieties.

You probably already have everything in your pantry.

If you love decadent bars, these are hands down the easiest way to satisfy a serious chocolate craving. They are even easier to slice than my Chocolate French Silk Brownies.

Marshmallow Brownies

• Publisher Storied Skillet
• Cuisine American
• Category Dessert, Brownies
• Prep Time 15 minutes
• Cook Time 25 minutes
• Servings 16
• Calories 240 calories
• Rating 4.8 939
• Tags marshmallow brownies, fudgy brownies, chocolate dessert, easy baking

Ingredients

• 1/2 cup unsalted butter, melted
• 2 tablespoons vegetable oil
• 1 cup granulated sugar
• 2 large eggs, room temperature
• 2 teaspoons vanilla extract
• 1/2 cup Dutch-process cocoa powder
• 1/2 cup all-purpose flour
• 1/2 teaspoon Diamond Crystal kosher salt (or 1/4 teaspoon fine table salt)
• 2 cups mini marshmallows
• 1/2 cup semi-sweet chocolate chips (for melting and drizzling)

Directions

1. Preheat your oven to 350°F (175°C) and line an 8x8-inch baking pan with parchment paper, leaving an overhang on the sides for easy removal.
2. In a medium bowl, whisk together the melted butter, vegetable oil, and granulated sugar until well combined.
3. Add the eggs one at a time, whisking vigorously after each addition, then stir in the vanilla extract until the mixture is pale and slightly thickened.
4. Gently fold in the cocoa powder, all-purpose flour, and kosher salt using a spatula just until the dry ingredients disappear. Do not overmix.
5. Spread the batter evenly into the prepared pan and bake for 20 to 22 minutes, or until a toothpick inserted into the center comes out with a few moist crumbs.
6. Remove the pan from the oven and immediately scatter the mini marshmallows in an even layer over the hot brownies.
7. Switch the oven to broil and return the pan to the top rack for 1 to 2 minutes until the marshmallows are puffed and golden brown. Watch them constantly to prevent burning!
8. Let the brownies cool completely in the pan, then drizzle with melted chocolate chips before slicing with a warm, clean knife.

Notes

• Salt Conversion: I always use Diamond Crystal kosher salt. If you are using Morton's or fine table salt, cut the volume in half to 1/4 teaspoon to avoid an overly salty base.
• Cocoa Science: Dutch-process cocoa powder is alkalized, which neutralizes its natural acidity. This allows the rich, chocolatey flavor compounds to shine without reacting unpredictably with the batter.
• Broiler Warning: Do not walk away from the oven when broiling the marshmallows. They go from perfectly toasted to a charred, smoky mess in literally five seconds.
• Storage Behavior: After a day in the fridge, the marshmallow layer will firm up slightly, making them much easier to slice cleanly, though they are best eaten at room temperature.
• More Bar Recipes: If you want a different twist on decadent chocolate bars, try my Peanut Butter Cup Brownies or Golden Grahams S'mores Bars.

Serving Suggestions

These brownies are incredibly rich on their own, but you can easily turn them into an over-the-top dessert experience with a few simple additions.

• Serve warm with a scoop of vanilla bean ice cream to balance the intense chocolate.
• Drizzle with warm caramel sauce right before serving for a turtle-style twist.
• Pair with a cold glass of milk or a hot espresso to cut through the sweetness.
• Crush graham crackers over the top to evoke a campfire s'mores vibe.
• Plate them alongside fresh raspberries to add a bright, tart contrast.

Storage and Reheating

Store these brownies in an airtight container at room temperature for up to three days. Because of the high sugar content in the marshmallows, they stay remarkably soft and fudgy without drying out.

Do not freeze them.

Freezing completely ruins the delicate, airy texture of the marshmallow topping, turning it rubbery once thawed. If you must store them longer, keep them in the fridge for up to a week.

When you are ready to eat, let them sit on the counter for twenty minutes to take the chill off. If you prefer that warm, gooey, fresh-out-of-the-oven pull, pop a single brownie in the microwave for exactly eight seconds.

Any longer and you will have a melted marshmallow disaster.

Ingredient Substitutes

If you find yourself missing an ingredient, don't panic—here are the easiest swaps that won't ruin the chemistry of your bake.

1. Butter: You can swap the unsalted butter for coconut oil, though it will add a subtle tropical flavor to the base.
2. Mini Marshmallows: If you only have large marshmallows, simply use kitchen shears to snip them into quarters before topping the brownies.
3. All-Purpose Flour: A 1:1 gluten-free baking flour blend works beautifully here because the recipe doesn't rely heavily on gluten development for structure.
4. Granulated Sugar: You can use light brown sugar instead, which will make the brownies even fudgier and add a slight caramel note.

Let me know how these turn out in your kitchen, especially if you manage to resist eating them straight out of the pan while they are still hot. If you are still craving gooey chocolate treats, you should definitely check out my Chocolate Ooey Gooey Cake next. Happy baking!