Chocolate Mousse Cake

Mousse Cake:

Place the chocolate and butter in a double boiler

Heat over low heat, stirring occasionally, until smooth

Add the confectioner's sugar and whisk until well combined

In a separate bowl, whip the egg whites until stiff peaks form

Fold the whipped eggs into the chocolate mixture until no white streaks remain

Heat the mixture in a double boiler over medium heat, stirring frequently, for 15 minutes

Remove from heat and let cool slightly, whisking occasionally

If desired, place the mixture over an ice bath and whisk for several minutes

Line a 22.5 x 12.5 x 7.5 cm cake pan with parchment paper, leaving a 2 inch border on all sides

Line the bottom of the pan with a layer of champagne biscuits, trimming to fit

Dip the biscuits in rum or cognac and arrange them in a single layer

Pour about 1/3 of the chocolate mixture over the biscuits, spreading evenly

Repeat the layers: 4 biscuits, rum/cognac, and 3 of the chocolate mixture, finishing with a biscuit top

Cover the cake with plastic wrap and refrigerate for 5-6 hours or overnight

If desired, place in the freezer until ready to serve

To serve, remove from refrigerator or freezer and decorate with whipped cream

If serving separately, pipe whipped cream on top.