• Preheat oven to 350 °F and grease and flour two round 8” or 9” baking pans.

Chocolate Mousse Cake Filling

• Stir the cocoa powder and hot water together.
• In a microwave, melt the chocolate chips just until smooth. Add the cocoa mixture to the melted chocolate chips and stir well to combine. Allow to cool to room temperature.
• In a separate large bowl, beat the cream and sugar until very stiff peaks form. Add the chocolate mixture and fold in with a spatula until well combined. Refrigerate until ready to use.

Chocolate Cake Instructions

• Stir together sugar, flour, cocoa powder, baking powder, baking soda and salt in large bowl.
• Add eggs, buttermilk, oil, and vanilla then mix until combined. Turn the mixer on low and spoon in the dry ingredients. Once incorporated, mix on medium speed for 2 minutes.
• Stir in boiling water (it will be a thin batter). Pour batter into prepared pans.
• Bake for about 30 to 35 minutes or until a toothpick inserted in the center comes out clean.
• Allow cake to cool in the pan for 5 minutes and then remove to wire cooling racks. Cool completely.

Chocolate Buttercream Frosting Instructions

• In a medium saucepan, add milk, cocoa, and butter. Bring to a boil. Remove from heat.
• Add powdered sugar and mix with electric beaters to get rid of any lumps. Allow to cool for 15-20 minutes, stirring occasionally.

Chocolate Mousse Cake Assembly Instructions

• Once cakes have cooled, use a sharp serrated knife to level each layer cake evenly. If making a 4-layer cake, slice each layer horizontally, so that you end up with four, thin, 8” or 9” cake pieces.
• Place your first cake layer on your cake serving plate or pedestal. Spread a big spoonful of mousse on top of that cake layer. Repeat with the remaining cake layers, adding a layer of mousse filling between each layer of cake.
• Use remaining mousse filling to spread it evenly around the entire outside and top of the cake. Refrigerate for 30 minutes.
• Remove cake from fridge and very slowly pour the cooled chocolate frosting over the top. Use a spatula or knife to gently spread the frosting evenly over the outside of the cake as you pour.