Servings: Serves 8
Place 3 racks in the oven. Preheat the oven to 350°.
Line 6 cookie sheets with buttered and floured parchment paper.
In a standing electric mixer, whip the egg whites on medium speed until foamy.
Begin to stream in 3/4 of the sugar (reserve the balance). This will take approximately 2–3 minutes.
Whip until soft but slightly firm peaks are formed.
Pour the room-temperature egg yolks all at once into the egg whites.
Ladle 1/4 of the egg base into the melted chocolate. Stir until homogeneous. Fold in the balance of the whipped egg mixture.
Divide the batter evenly between six cookie sheets. Bake 3 at a time for 8 minutes. Turn, and continue to bake for 3–4 minutes.
Remove from oven and cool.
For Chocolate Mousse Filling
Whip the heavy cream until soft peaks are formed.
Over a double boiler, in a medium-size mixing bowl, combine the milk chocolate and bittersweet chocolate. Stir until melted and reserve.
Over a double boiler, whip together the yolks, eggs and sugar. When it reaches 110°, remove from heat.
Fold 1/3 of the egg mixture into the melted chocolate. Fold the balance of the egg mixture until homogeneous. Fold in the heavy cream.
For Coffee Syrup
Combine all ingredients and bring to a boil in a small saucepan. Reserve.
To assemble the cake: Line the presentation tray with a cake layer. Brush with coffee syrup. Top with chocolate mousse. With a metal offset spatula, "schmear" evenly. Continue layering with a balance of cake and mousse.