*** I like to layer this in little souffle cups instead of making an actual cake.
Ingredients
For the cake and mousse:
1 18 .25-ounce box devil's food cake mix (plus
required ingredients)
14 ounces bittersweet chocolate, chopped
12 tablespoons (1 1/2 sticks)
unsalted butter, diced
1/4 cup strong coffee
10 large eggs, separated
1 1/2 cups plus 6 tablespoons sugar
1 teaspoon vanilla extract
1/2 teaspoon salt
2 cups cold heavy cream
For the shell and sauce:
12 ounces bittersweet chocolate, chopped
3/4 cup heavy cream
5 tablespoons light corn syrup
2 tablespoons unsalted butter
To serve:
1 1/2 cups cold heavy cream
1 tablespoon sugar
1 pint vanilla ice cream
Directions
Make the cake: Prepare the cake mix as the label
directs for a 9-by-13-inch cake. Bake; cool slightly in the pan, then invert
onto a rack to cool completely.
Clean out the cake pan and line it with plastic
wrap. Cut the cake in half lengthwise, then in thirds crosswise to make 6
rectangles. Using a serrated knife, slice each rectangle in half to make two
layers. Arrange half of the pieces snugly in the cake pan. Crumble the remaining
pieces and press tightly into 6 small balls; arrange 1 cake ball in the center
of each cake rectangle in the pan.
Make the mousse: Heat the chocolate, butter,
coffee and 1/4 cup water in a heatproof bowl set over a saucepan of simmering
water (do not let the bowl touch the water), stirring, until melted. Remove the
bowl from the pan; stir until cool. Reserve the simmering water. Fill a large
bowl with ice water.
Whisk the egg yolks, 1 1/2 cups sugar and 2
tablespoons water in a separate large heatproof bowl. Set the bowl over the
saucepan of simmering water and whisk until pale yellow, 6 to 8 minutes. Add
the chocolate-coffee mixture and the vanilla and whisk until combined, about 2
minutes. Remove the bowl from the pan and set in the bowl of ice water; whisk
until slightly cool but not thick, about 4 minutes.
Beat the egg whites and salt in a bowl with a
mixer until foamy. Add 2 tablespoons sugar and beat until almost stiff; gently
fold into the chocolate-yolk mixture to make a dark chocolate mousse. Spread 5
cups over the cake and cake balls. Freeze until firm on top, about 30 minutes.
Beat the heavy cream and the remaining 4
tablespoons sugar until soft peaks form; fold into the remaining mousse. Remove
the cake from the freezer; spread with the light chocolate mousse, cover with
plastic wrap and freeze until firm, at least 6 hours or overnight.
Make the chocolate shell: Stir the chocolate,
heavy cream and 4 tablespoons corn syrup in a heatproof bowl set over a
saucepan of simmering water (do not let the bowl touch the water) until melted.
A spoonful at a time, spread half of the shell mixture over the frozen mousse.
Return to the freezer.
Make the chocolate sauce: Add the remaining 1
tablespoon corn syrup and the butter to the remaining chocolate shell mixture.
Microwave 30 seconds, then stir until glossy.
To serve the cake, beat the heavy cream with a
mixer until foamy. Add the sugar and beat until soft peaks form. Remove the
cake from the freezer; invert onto a baking sheet and unmold, then invert again
onto a platter, chocolate shell-side up.
Cut the cake in half lengthwise using a warm
knife, then cut into thirds crosswise to make 6 rectangles; cut each rectangle
in half diagonally to make 2 triangles. Top each triangle with whipped cream,
ice cream and the prepared chocolate sauce.
