Beat in flour alternately with milk. Add vanilla and beat. Spoon 2-3 tablespoons batter into greased and floured cake pans. Cook for about 1-2 minutes each in 405 degree oven until lightly done.
Pipe a 1/2-inch-tall border of icing around edge of first cake layer. Spoon half of chocolate mousse (about 2 cups) onto center of cake, and spread evenly within border using a small offset spatula.
Unmold onto a wire rack and cool. Level the surface of each cake; spread a layer of chocolate icing between each layer of cake and frost the outside of the cake with the remaining icing.
Remove from the heat and stir in the chocolate ... Slice each cake in half horizonatally. Put one cake half on a wire rack and smooth a layer of whipped cream on top. Continue this process ...
A cake tester should come up mainly clean but with a few sticky chocolate crumbs clinging to ... wrapped in a double layer of clingfilm, followed by a layer of foil. Unwrap and defrost at room ...