Chocolate Ganache Mousse Cake

Preheat oven to 350ºF. Grease and line the sides and bottoms of three 5-inch springform pans with parchment papers.

For the chocolate cake, in a large bowl, mix together sugar, flour, cocoa powder, baking powder, baking soda and salt. Crack in the egg, spoon in sour cream, and pour in oil and vanilla. Mix with a wooden spoon until just combined.
Pour in boiling water, and slowly mix until smooth and liquid.

Divide the batter among the prepared pans, smoothing the surface with a spatula. Bake 20–25 minutes or until a toothpick inserted into the cake comes out clean. Let cakes cool completely in the pans.

To prepare mousse, make a double boiler and bring the water to a soft simmer. Put chocolate, butter and espresso in a heat resistant bowl and leave to melt. Put a mixing bowl in the freezer.

Beat the egg whites until soft peak forms. Add sugar and continue beating until it becomes stiff and forms peak. Transfer to another bowl. Set aside.

Using the same bowl that you used to whip the egg whites, beat egg yolks until light and creamy. Mix in the chocolate mixture. Fold the whipped egg whites in the chocolate and egg yolk mixture.

Put cream in the bowl from the freezer and whip until it becomes stiff. Add whipped cream to the chocolate mixture and fold with a spatula until it becomes one mixture.

Pour the chocolate mixture evenly into the cake pans. Juggle to lightly level the top. Keep in the refrigerator overnight.

Prepare ganache before serving. Place chocolate, heavy cream and corn syrup in a medium heatproof bowl over a pot of simmering water. Stir the mixture using a wooden spoon until melted and smooth, about 5 minutes. Remove from heat and let cool slightly.

Gently loosen the springfrom rings to release the cakes. Peel off the parchment papers. Place the cakes on serving plate(s). Pour ganache over the top of the cakes. Use an offset spatula to gently push the ganache to the sides to create dripping effect. Garnish with chocolate shavings and sprinkles.