Chocolate Mousse Cake

Moist dark chocolate cake that's topped with an easy chocolate mousse.

Course Dessert

Cuisine American

Prep Time 50

Cook Time 30

Total Time 1 20

Servings servings

Calories 449kcal

Preheat oven to 350 F. Grease a 9x13-inch baking pan. Set aside.
In a medium bowl, whisk together flour, sugar, cocoa powder, baking soda, baking powder, and salt. Set aside.
1 ¾ cups all-purpose flour, 1 ¾ cups granulated sugar, ¾ cups unsweetened cocoa powder, 2 teaspoons baking soda, 1 teaspoon baking powder, 1 teaspoon kosher salt
In a large bowl, whisk together buttermilk and vegetable oil.
1 cup buttermilk, ½ cup vegetable oil
Whisk in eggs one at a time.
2 large eggs
Stir in dry ingredients until just combined.
Add hot water and vanilla.
2 teaspoons vanilla extract, 1 cup hot water
Whisk until just combined.
Pour batter into prepared baking dish.
Bake 30-40 minutes, or until wooden toothpick inserted in the center comes out clean.
Cool to room temperature.

To make the chocolate mousse, add mini marshmallows, chocolate, and milk to a large, heavy saucepan.
1 ½ cups mini marshmallows, 8 ounces semisweet baking chocolate, ½ cup milk
Cook over low heat, stirring constantly, until melted and well-combined.
Remove from heat, and cool completely.
In a large bowl, beat whipping cream and vanilla together to soft peak stage.
2 cups cold heavy whipping cream, ½ teaspoon vanilla extract
Fold whipped cream into cooled chocolate mixture.
Spread over cooled cake.
Chill for at least 30 minutes, or until ready to serve.
Refrigerate any leftovers.

Cocoa powder: I use regular unsweetened cocoa powder in this recipe. I've also used Hershey's special dark cocoa powder. However, I haven't tried Dutch-processed cocoa powder with this cake.
Salt: If you don't have kosher salt, use 1/2 teaspoon table salt instead.
Buttermilk: Regular or low-fat will work. If you don't have buttermilk, you can make a quick substitute with this recipe.
Water: I use hot tap water about (150F).
Semisweet baking chocolate: If you'd like a sweeter mousse, you can use milk baking chocolate.
Milk: Any milk from skim to whole milk will work.
Nutrition facts are estimates.