Ingredients
Method
- Preheat the oven to 350°F (177°C). Grease four 8-inch or 9-inch cake pans, line with parchment paper rounds, then grease the parchment paper. Parchment paper helps the cakes seamlessly release from the pans.
- In a large bowl, whisk together the flour, sugar, cocoa powder, espresso powder, baking soda, baking powder, and salt. Set aside.
- In another bowl, combine the sour cream, oil, and eggs using a mixer or whisk. Beat on medium-high speed until well mixed. Add the buttermilk and vanilla, and mix until smooth.
- Slowly add the dry ingredients into the wet mixture, then pour in the hot water or coffee. Mix on low speed until just combined. Fold in the mini chocolate chips, if using. Divide the batter evenly among the prepared pans.
- Bake the cake layers for 19–23 minutes or until a toothpick inserted in the center comes out clean. Cool in the pans for 1 hour. Afterward, remove from pans and peel off the parchment paper. Place the cakes on a cooling rack to finish cooling.
- For the mousse, whisk the hot water and cocoa powder together in a small bowl until smooth. Melt the chopped chocolate using a double boiler or microwave in increments.
- Once melted, combine the hot water/cocoa mixture with the melted chocolate. Stir until thick and smooth. Set aside.
- In a large bowl, whip the cold heavy cream, confectioners’ sugar, and vanilla until medium peaks form. Fold in the chocolate mixture gently. Do not overmix. Refrigerate the mousse for at least 2 hours or up to 2 days.
- Once the cakes have cooled, level the tops if needed. Place one cake layer on your serving plate, spread with 1.5 cups of mousse, then add the second layer upside down. Repeat the process, adding mousse between each layer. Finish by covering the entire cake with mousse.
- Refrigerate the cake for at least 1 hour or up to 4 hours to firm up.
- For the ganache, heat the cream over medium heat until it begins to simmer. Pour it over the chopped chocolate and let it sit for 2–3 minutes to soften. Stir until smooth. refrigerate for 30 minutes to 1 hour to thicken.
- Once thickened, pour the ganache over the chilled cake and smooth it out with a spatula. Garnish with fresh berries or chocolate shavings if desired.
- Serve immediately or chill for 4–6 hours before serving. The cake can be served at room temperature or chilled.
Nutrition
Notes
This cake is perfect for any special occasion with its rich layers of chocolate mousse and ganache. The optional espresso powder deepens the flavor, while fresh berries or chocolate shavings make for a beautiful garnish.