Chocolate Mousse Cake
Servings: 12 servings
Calories: 422kcal
Chocolate mousse cake is the best of both worlds. This decadent dessert has a layer of chocolate cake on the bottom and a chocolate mousse layer on the top.
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US Customary - Metric
Ingredients
For the cake:
- 1 cup all purpose flour
- 4 ½ tablespoon unsweetened natural cocoa powder (not Dutch processed cocoa-see notes)
- 1 teaspoon baking powder
- ½ teaspoon baking soda
- ½ teaspoon salt
- ½ cup granulated sugar
- ½ cup packed brown sugar
- ¼ cup unsalted butter (melted)
- 2 tablespoon vegetable oil
- ½ teaspoon vanilla extract (or vanilla paste)
- ½ cup buttermilk (or regular milk mixed with ½ teaspoon lemon juice or vinegar)
- 2 large eggs
- ¼ cup hot coffee (or hot water)
For the chocolate mousse:
- 1 cup chopped semisweet chocolate (I used about 1 ½ Baker's bars)
- 2 cups heavy cream (sometimes called whipping cream, not whipped cream - see notes)
- ½ cup sifted confectioner's sugar
Instructions
For the cake:
- Preheat oven to 325 degrees. Grease the bottom and half way up the sides of a 9" springform pan. (You will need to use a springform pan for this as you will not be able to easily remove the entire cake from a regular pan once the mousse is added and chilled.)
- In a large mixing bowl, add the dry ingredients (flour, cocoa powder, baking powder, baking soda, salt and sugar). Mix well with a whisk.
- If not using buttermilk, then add the regular milk and lemon juice (or vinegar) in a measuring cup and mix well. Let it sit for about 5 minutes. (You're basically making a buttermilk substitute by doing this.) If the mixture starts looking a little clumpy, that's normal.
- Add all the liquid ingredients (except for the hot coffee or water) to a mixing bowl and whisk well.
- Pour the liquid ingredients into the dry ingredients and mix with an electric mixer on medium just until the ingredients are combined. Scrape down the sides of the bowl and mix again for about 5-10 seconds more or until well combined.
- Add the hot coffee (or hot water) and mix until well combined.
- Be careful not to over mix. Once it’s combined, stop mixing. You don’t want to mix for several minutes, that’s too long. Scrape down the sides of the bowl and mix again for about 5-10 seconds.
- Pour the batter into the greased springform pan and bake at 325 degrees for approximately 35-40 minutes. It's helpful to put a cookie sheet on the rack below your pan just in case the springform pan doesn't seal tight and has a few leaks.
- Set the baked cake on a wire rack to cool completely, then cover the cake and chill in the fridge until ready to add the chocolate mousse. Do not remove the cake from the pan yet. You can run a knife around the edge to loosen the cake a bit though.
For the chocolate mousse:
- Place the chopped chocolate in a small heat safe bowl and set aside.
- In a small saucepan, heat 1 cup of the heavy cream until almost boiling.
- Pour the hot cream over the chocolate and let it sit for about 5 minutes, then stir well until smooth. Be patient while stirring as it takes a several minutes to mix well.
- Chill in the fridge for about 25-30 minutes, stirring every now and then. It needs to be cooled down (not cold) for the next step.
- Add the other 1 cup of heavy cream to a medium mixing bowl and beat on medium high while slowly adding in the sifted confectioners sugar. Beat on high until stiff peaks form, about 1 minute depending on your mixer.
- Transfer the chocolate mixture into a large bowl and make sure it's smooth and no longer warm.
- Very carefully fold the whipped heavy cream into the chocolate mixture. You can do this slowly in three steps if you need to. Make sure to fold it in delicately and not to stir it.
- Add the chocolate mousse on top of the chilled chocolate cake in the springform pan. Make sure the chocolate cake has fully chilled before you do this.
- Cover and refrigerate for at least 6 hours or overnight. It needs to be very cold and firm when you take off the sides of the springform pan.
- To serve, run a hot knife just around the inside of the springform pan and then unsnap and remove the outside pan ring.
- Before serving, you can whip any leftover heavy cream or use cool whip and pipe around the top of the cake then add sprinkles or chocolate shavings.
Notes
*Dutch processed cocoa is different from regular unsweetened cocoa powder. See the FAQs in this post to explain why a recipe calls for one and not the other.
*Heavy cream is sometimes called whipping cream, but it is not the same thing as whipped cream (Cool Whip). Cool Whip will not work for the mousse recipe. See the FAQs in this post that will explain in more detail.
This cake will keep for several days, covered and stored in the fridge.
Nutritional values are an estimate.
Make sure to check out the TIPS & FAQs for this recipe in the blog post, which may answer questions you may have.
*This recipe card may contain affiliate links. As an Amazon Associate, I earn from qualifying purchases.
Nutrition
Calories: 422kcal | Carbohydrates: 41g | Protein: 4g | Fat: 28g | Saturated Fat: 17g | Trans Fat: 1g | Cholesterol: 94mg | Sodium: 184mg | Potassium: 226mg | Fiber: 2g | Sugar: 28g | Vitamin A: 765IU | Vitamin C: 1mg | Calcium: 78mg | Iron: 2mg