Chocolate Mousse Brownies
Indulge in these rich and decadent Chocolate Mousse Brownies featuring a fudgy brownie base topped with airy chocolate mousse and optional chocolate drizzle.
Ingredients
Brownie Base
- 4 ounces semisweet chocolate baking bar, chopped
- ¼ cup salted butter
- ⅓ cup vegetable oil
- 1½ cups granulated sugar
- 2 whole eggs, room temperature
- 2 teaspoons pure vanilla extract
- ¾ cup all-purpose flour, spooned and leveled
- ½ cup unsweetened Dutch-processed cocoa powder
- ½ teaspoon baking powder
- ½ teaspoon table salt
Chocolate Mousse
- 4 ounces semisweet chocolate baking bar, chopped
- 1 cup mini marshmallows
- ¼ cup whole milk
- 1 tablespoon whole milk additional for chocolate mousse
- 1¼ cups cold heavy cream
- Chocolate syrup for drizzling optional garnish
Instructions
Preparation of Brownie Base
- Preheat the oven to 350°F (180°C). Line a 9×9-inch baking pan with parchment paper, leaving overhang for easy lifting.
- In a microwave-safe bowl, melt the chopped chocolate and butter in 20-second intervals (or use a double boiler). Stir in vegetable oil until smooth.
- In a large mixing bowl, add the granulated sugar.
- Whisk in the chocolate mixture until fully combined.
- Add the eggs one at a time, whisking gently until just incorporated. Avoid over-beating.
- Add vanilla extract.
- Sift flour, cocoa powder, baking powder, and salt into the bowl. Fold gently until no dry streaks remain.
- Spread the batter evenly into the prepared pan.
- Bake for 22–25 minutes, until edges are set but the center looks slightly soft.
- Let the brownies cool completely in the pan.
Preparation of Chocolate Mousse
- Place the mixing bowl and whisk attachment in the freezer.
- In a medium saucepan over low heat, combine the chopped chocolate, mini marshmallows, and milk.
- Stir constantly until fully melted and smooth.
- Let the mixture cool to room temperature—this prevents deflating the whipped cream.
- In a chilled bowl, beat the heavy cream until soft peaks form.
- Reduce the speed to low and slowly add the cooled chocolate mixture.
- Increase mixer speed to high and beat until stiff peaks form. (Do NOT overwhip.)
- Spread the mousse evenly over the fully cooled brownies.
- Cover and chill in the refrigerator for 2 hours.
Serve and Garnish
- Once chilled, lift brownies from the pan and slice into 12 squares.
- Drizzle with chocolate syrup if desired.
- Keep refrigerated until serving.
Notes
Line the pan with parchment for clean removal and sharp edges. Do not overbake the brownies. Slightly underdone centers make them fudgier. Cool brownies completely before adding mousse—warm brownies melt the topping. Cool chocolate mixture fully to prevent collapsing the whipped cream. Chill for best results — longer chilling gives cleaner cuts and better texture. Store in the refrigerator for up to 4 days or freeze for up to 2 months.