-
1
Preheat oven to 350 degrees F (175 degrees C). Grease and flour two 9-inch round baking pans.
-
2
Mix cake mix, 1 cup water, oil, and eggs in a large bow until well blended. Pour batter into prepared baking pans.
-
3
Bake in the preheated oven until a toothpick inserted into the center comes out clean, 26 to 31 minutes. Cool in the pans for 10 minutes before removing to cool completely on a wire rack. Slice one cakes in half horizontally and place one half in a 10-inch springform pan. Save remaining 3/4 cake for another use.
-
4
Melt chopped baking chocolate and cream cheese in a large microwave-safe bowl in 30-second intervals, stirring after each melting, for 1 to 3 minutes (depending on your microwave). Set aside to cool.
-
5
Mix 1 teaspoon gelatin with 1 tablespoon cold water in a small bowl for 1 minutes; add boiling water and stir until gelatin is dissolved. Allow to cool.
-
6
Beat 3/4 cups heavy whipping cream until foamy in a large bowl. Add 1/2 teaspoon sugar and gelatin mixture; continuing to beat until stiff peaks form. Lift your beater or whisk straight up: the whipped cream should form a sharp peak that holds its shape. Fold about 1/4 the whipped cream into the cooled chocolate cream cheese mixture until well blended; fold remaining whipped cream into chocolate mixture to create a mousse. Spread mousse over cake arranged in springform pan. Refrigerate while preparing next layer.
-
7
Beat egg yolks in a large bowl until yolks are a pale yellow. Beat in 1/4 cup sugar, 3 tablespoons flour, and 1 teaspoon gelatin until mixed.
-
8
Bring 1 3/4 cups heavy whipping cream and vanilla extract to a boil in a saucepan; lower heat to medium. Pour about 1/2 cup hot cream into egg mixture while stirring; stir remaining cream mixture into bowl. Pour cream mixture through a strainer into the saucepan; continue cooking and stirring until mixture is thick enough to coat the back of a spoon, about 10 minutes. Allow custard to cool, then pour over mousse layer in springform pan. Place cake in freezer while making remaining layer.
-
9
Reserve 1/2 cup chocolate chips; pour remaining chocolate chips in a large bowl.
-
10
Bring 1 1/2 cups heavy whipping cream and butter to a boil in a clean saucepan. Pour cream mixture into the bowl over chocolate chips. Stir until smooth and chocolate is melted. Allow mixture to cool until chocolate ganache begins to thicken.
-
11
Remover cake from freezer and remove pan collar from the springform pan. Pour chocolate ganache over cake; use a spatula to evenly spread chocolate over top and sides of the cake. Press reserved 1/2 cup chocolate chips along the side of the cake. Refrigerate until ready to serve.
