Chocolate Mousse Brownies are the ultimate indulgence for chocolate lovers. This decadent dessert combines a dense, fudgy brownie base with a light and airy chocolate mousse topping. The contrast between the rich brownie and the creamy mousse creates a delightful texture, and the optional drizzled ganache adds a glossy finish that makes every slice feel special. If you’re looking for a dessert that’s both impressive and accessible, this one fits the bill beautifully.
Why You’ll Love These Chocolate Mousse Brownies
You’ll love this Chocolate Mousse Brownies recipe because it takes two beloved desserts, brownies and chocolate mousse, and brings them together in perfect harmony. The brownie layer gives you that satisfying chew and deep cocoa flavor, while the mousse adds a cloud-like lightness and creamy finish. It’s a layered treat that feels gourmet but can absolutely be made at home with everyday ingredients. Whether you’re baking for a gathering, a special occasion, or simply treating yourself, this recipe delivers on flavor, texture, and wow-factor.
Ingredients
For the Brownies:
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¾ cup butter, melted
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1½ cups sugar
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1 tsp vanilla extract
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2 eggs
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½ cup cocoa powder
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½ tsp salt
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¾ cup all-purpose flour
For the Mousse:
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¾ cup miniature marshmallows
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4 oz (1 bar) semi-sweet chocolate, chopped
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¼ cup milk
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1 cup heavy whipping cream
Optional Ganache for Drizzling:
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½ cup chocolate chips
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¼ cup heavy whipping cream
Step-by-Step: How to Make Chocolate Mousse Brownies
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Preheat and prepare the pan. Preheat the oven to 350 °F (≈175 °C). Line a 9×9-inch square baking pan with foil, leaving an overhang on the sides for easy removal. Liberally spray the foil with cooking spray; set pan aside.
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Make the brownie batter. In a large bowl, combine the melted butter and sugar until smooth. Add the eggs one at a time, stirring well after each addition, then stir in the vanilla extract. Next, add the cocoa powder, salt, and flour, stirring until the batter comes together into a soft mixture.
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Bake the brownies. Pour the batter into the prepared pan and smooth into an even layer. Bake for about 22–25 minutes, or until a toothpick inserted near the center comes out clean or with moist (not wet) crumbs. Once done, let the brownie layer cool completely in the pan.
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Make the mousse layer. In a large saucepan over low heat, combine the miniature marshmallows, chopped semi-sweet chocolate, and milk. Stir frequently until everything is melted and smooth. Remove from heat and allow this chocolate-marshmallow mixture to cool completely (about 15–20 minutes) so it won’t deflate the whipped cream later.
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Whip the cream. Meanwhile, in a stand mixer (or using hand beaters), whip the heavy whipping cream until stiff peaks form. This means the cream holds its shape when you lift out the whisk.
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Fold mousse and assemble. Once the chocolate mixture is cooled, gently fold it into the whipped cream—start by mixing in a small portion to lighten the chocolate mixture, then fold in the rest until fully combined and still airy. Spread the mousse evenly over the cooled brownie layer in the pan.
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Chill to set. Refrigerate the assembled brownies for at least 1 hour (longer is fine) so that the mousse layer firms up.
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Add ganache (optional). If you’d like a glossy finish, make the ganache: Combine the chocolate chips and heavy cream in a microwave-safe bowl. Heat on high for 15–20 seconds, stir, then continue heating in 10-second increments until the mixture is smooth. Drizzle this over the set mousse layer just before serving.
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Serve. Use the foil overhang to lift the dessert out of the pan, slice into squares, and serve chilled or at room temperature (your preference).
Helpful Tips
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Let the brownie layer cool completely before adding the mousse; otherwise the mousse may melt into the brownie layer and you’ll lose the nice separation of textures.
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When whipping the cream, make sure your bowl and beaters are chilled for best results (cold surfaces help the cream reach stiff peaks faster).
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When folding the chocolate mixture into the whipped cream, fold gently—do not over-mix or deflate the airy texture.
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For neater slices, use a sharp knife warmed under hot water and wiped dry between cuts—this helps you get clean edges and prevents dragging the mousse.
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If your mousse mixture seems to thicken too much (or start to set) before spreading, spread it quickly while it’s still pliable.
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Make these ahead of time! They chill well—prepping them earlier in the day or even the evening before can free you up for serving later.
Substitutions And Variations
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Chocolate type: You can substitute semi-sweet chocolate with dark chocolate if you prefer a more intense cocoa flavor, or milk chocolate for a sweeter result.
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Marshmallows: If you don’t have miniature marshmallows, you can use regular marshmallows (measure accordingly) or skip them, just melt chocolate and milk mixture.
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Flour substitute: Use whole-wheat pastry flour or a gluten-free all-purpose flour blend if you need gluten-free, but be aware texture may shift slightly.
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Flavor additions: Add a pinch of espresso powder or instant coffee to the brownie batter to deepen the chocolate flavor. A splash of vanilla or almond extract in the mousse adds subtle nuance.
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Layer twist: For a fun variation, you can add a thin layer of caramel or peanut butter between the brownie and mousse layers.
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Top garnish: Instead of ganache drizzle, you could top with chocolate shavings, crushed cookies, chopped nuts, or fresh berries for contrast and color.
Storage Instructions
Keep the brownies in a sealed airtight container and refrigerate to maintain freshness. They will stay delicious for up to 3–4 days. If you want to serve at room temperature, remove from the fridge about 15–20 minutes beforehand. Avoid freezing, as the mousse texture may change when thawed.
Nutritional Information
While this is a rich dessert, here is an approximate nutritional snapshot per serving (assuming 9 servings total):
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Calories: ~400–450 kcal
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Fat: ~25–30 g (including saturated fat from butter and cream)
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Carbohydrates: ~40–50 g (mostly from sugar and flour)
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Protein: ~5–7 g
Serving Suggestions
Serve the Chocolate Mousse Brownies chilled or at slightly below room temperature for the best texture contrast. Pair with:
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A dollop of whipped cream or a scoop of vanilla ice cream to balance the richness.
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Add a pop of color and a refreshing touch with fresh berries like raspberries or strawberries.
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Pair with a warm drink like coffee, espresso, or a decadent hot chocolate for an extra layer of indulgence.
Frequently Asked Questions About Chocolate Mousse Brownies
Can I use a different size baking pan?
Yes. The recipe uses a 9×9-inch square pan. If you use a larger pan (for example 9×13), the layers will be thinner and baking time for the brownie layer may be shorter, so monitor closely and test with a toothpick. If you use a smaller pan, you may need slightly more batter or mousse to maintain layer thickness.
Can I skip the marshmallows in the mousse?
Absolutely. The marshmallows help create a textured, melt-together chocolate layer but aren’t strictly necessary. You can melt the chocolate and milk only to create a simpler chocolate base for the mousse layer, which will still work beautifully.
My mousse turned grainy or separated—what happened?
This can happen if the melted chocolate mixture is too hot when you fold in the whipped cream, or if the whipped cream is too soft. Make sure the chocolate mixture has cooled enough so it won’t melt the cream, and that you’ve whipped the cream to firm peaks before folding. Gentle folding and temperature control are key.
Can I make this ahead of time?
Yes. In fact, chilling overnight often enhances both the texture and flavor fusion of brownie and mousse. Just cover the pan in the fridge and bring out 15–20 minutes before serving if you prefer less-cold dessert.
Final Thoughts
Thank you for joining me on this indulgent baking adventure with this Chocolate Mousse Brownies recipe. I hope you enjoy the ease of preparation and the rich, layered flavor as much as I do. There’s something deeply satisfying about the contrast of a fudgy brownie base topped with creamy chocolate mousse, and knowing you made it yourself only adds to the delight. Wishing you many happy moments in the kitchen, lots of smiles around the plate, and pure enjoyment of every luscious bite. Thank you for being part of the food-loving community. Happy baking!
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Chocolate Mousse Brownies
- Total Time: 1 hour 20 minutes (including chilling)
- Yield: 9 brownies 1x
Description
Chocolate Mousse Brownies are a layered dessert masterpiece featuring a fudgy brownie base topped with a creamy chocolate mousse. Easy to make with simple pantry staples, this show-stopping treat is perfect for parties or just a sweet family dessert.
Ingredients
For the Brownies:
¾ cup butter, melted
1½ cups sugar
1 tsp vanilla extract
2 eggs
½ cup cocoa powder
½ tsp salt
¾ cup all-purpose flour
For the Mousse:
¾ cup miniature marshmallows
4 oz semi-sweet chocolate, chopped
¼ cup milk
1 cup heavy whipping cream
Optional Ganache:
½ cup chocolate chips
¼ cup heavy cream
Instructions
-
Preheat and prepare the pan. Preheat the oven to 350 °F (≈175 °C). Line a 9×9-inch square baking pan with foil, leaving an overhang on the sides for easy removal. Liberally spray the foil with cooking spray; set pan aside.
-
Make the brownie batter. In a large bowl, combine the melted butter and sugar until smooth. Add the eggs one at a time, stirring well after each addition, then stir in the vanilla extract. Next, add the cocoa powder, salt, and flour, stirring until the batter comes together into a soft mixture.
-
Bake the brownies. Pour the batter into the prepared pan and smooth into an even layer. Bake for about 22–25 minutes, or until a toothpick inserted near the center comes out clean or with moist (not wet) crumbs. Once done, let the brownie layer cool completely in the pan.
-
Make the mousse layer. In a large saucepan over low heat, combine the miniature marshmallows, chopped semi-sweet chocolate, and milk. Stir frequently until everything is melted and smooth. Remove from heat and allow this chocolate-marshmallow mixture to cool completely (about 15–20 minutes) so it won’t deflate the whipped cream later.
-
Whip the cream. Meanwhile, in a stand mixer (or using hand beaters), whip the heavy whipping cream until stiff peaks form. This means the cream holds its shape when you lift out the whisk.
-
Fold mousse and assemble. Once the chocolate mixture is cooled, gently fold it into the whipped cream—start by mixing in a small portion to lighten the chocolate mixture, then fold in the rest until fully combined and still airy. Spread the mousse evenly over the cooled brownie layer in the pan.
-
Chill to set. Refrigerate the assembled brownies for at least 1 hour (longer is fine) so that the mousse layer firms up.
-
Add ganache (optional). If you’d like a glossy finish, make the ganache: Combine the chocolate chips and heavy cream in a microwave-safe bowl. Heat on high for 15–20 seconds, stir, then continue heating in 10-second increments until the mixture is smooth. Drizzle this over the set mousse layer just before serving.
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Serve. Use the foil overhang to lift the dessert out of the pan, slice into squares, and serve chilled or at room temperature (your preference).
Notes
For clean slices, chill longer and use a warm knife. Store in the fridge for up to 4 days in an airtight container.
- Prep Time: 25 minutes
- Cook Time: 25 minutes
- Category: Dessert
Nutrition
- Serving Size: 1 brownie
- Calories: 430 kcal
- Sugar: 36 g
- Carbohydrates: 48 g
- Protein: 5 g