Fudgy brownies filled with Oreo cookies, crowned with fluffy marshmallow frosting and finished with extra Oreos. These Marshmallow Oreo Brownies are as indulgent as they sound.
I’ve made plenty of decadent desserts, but this recipe might be the most over-the-top treat yet on Just So Tasty.
Marshmallow. Oreo. Brownies.
We start with intensely fudgy chocolate brownies, tuck a layer of Oreo cookies inside, top them with airy marshmallow frosting, and finish with more Oreos on top.
If you’ve tried Dairy Queen’s Brownie Earthquake, this is the brownie-only equivalent—rich, chocolatey, and utterly satisfying.
And completely worth every calorie. 
The brownies are a one-bowl recipe made with oil and cocoa for a deep chocolate flavor and dense, fudgy texture. A small amount of flour keeps them chewy and rich. The batter comes together in about five minutes.
Spread half the batter in the pan, arrange the Oreo cookies in a layer, then pour the remaining batter over them so the cookies are embedded in the brownies.
Once baked and cooled, the brownies get a generous spread of marshmallow frosting. This frosting is light and pillowy—so good that many prefer it to traditional buttercream.
To make the marshmallow frosting:
- Beat room-temperature butter with powdered sugar until combined.
- Fold in marshmallow cream and whip until fluffy.
- If it’s too thick, add a tablespoon of milk or cream to reach the desired consistency.
It only takes a few minutes to reach marshmallow bliss. I use a thick layer of frosting and top everything with crushed Oreos for extra crunch and chocolate flavor.
The result is outrageously fudgy brownies with Oreo overload and a cloud of marshmallow on top. These are best served once the frosting is set so the slices hold together.
Try these brownies—you’ll get serious chocolate and marshmallow satisfaction in every square.
For more Oreo desserts, you might also enjoy the following recipes.
- Oreo Ice Cream Cake
- Oreo Brownies
- Oreo Cheesecake
Marshmallow Oreo Brownies
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Ingredients
For the Brownies
- 1/2 cup vegetable oil
- 3/4 cup granulated sugar
- 1/2 cup brown sugar, packed
- 3/4 cup cocoa powder, (Dutch-processed recommended)
- 1 teaspoon vanilla extract
- 1/4 teaspoon salt
- 2 large eggs
- 1/2 cup all-purpose flour
- 16 Oreo cookies
For the Marshmallow Frosting
- 1/3 cup unsalted butter, softened to room temperature
- 1/2 cup powdered sugar, sifted
- 1/2 cup marshmallow cream
- 1 tablespoon milk or cream, optional
- 8 Oreo cookies, crushed for topping
Instructions
Make the Brownies
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Preheat the oven to 350°F. Line an 8×8-inch pan with aluminum foil and grease with nonstick spray or butter.
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In a medium bowl, combine the oil and sugars. Warm briefly in the microwave (about 30 seconds) and stir until smooth. Add the cocoa powder, salt, and vanilla. When the mixture has cooled slightly, whisk in the eggs, then fold in the flour until just combined.
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Spoon half the batter into the prepared pan. Arrange the 16 Oreo cookies in a single layer over the batter, then spoon the remaining batter over the cookies and spread gently. It’s okay if some cookies peek through.
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Bake for 22–24 minutes, or until the top is set and the sides begin to pull away. Let the brownies cool completely in the pan.
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Make the frosting: Beat the butter and powdered sugar on low until combined, then increase speed and whip until light and fluffy. Fold in the marshmallow cream. If too thick, add 1 tablespoon of milk or cream and mix until smooth.
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Lift the cooled brownies from the pan using the foil. Spread the marshmallow frosting evenly with a flat knife, sprinkle the crushed Oreos on top, then slice into squares and serve.
Nutrition
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Love Brownies? Here’s Some of My Other Favorites
Nutella Brownies
Fudge Brownie Pie
Cream Cheese Brownies