You will need:
220 g dark chocolate, chopped
140 g butter
4 egg yolks
6 egg whites
35 g sugar
125 ml cream
What to do:
1. Melt the chocolate and butter in a double boiler over low heat. Stir until no lumps remain.
2. Allow the mixture to cool slightly, then whisk in the egg yolks one at a time.
3. Beat the egg whites until soft peaks form. Whisk one-fourth of the whipped egg whites into the chocolate mixture to lighten, then fold in the remaining whites.
4. Whip the cream to soft peaks. Allow the mousse to cool, then fold in the whipped cream. Make sure no streaks of egg white or cream remain.
5. Spoon the mousse into serving bowls and garnish with whipped cream, fresh mint and shaved chocolate or berries. Or chill the mousse completely, then pipe it into bowls or baked tartlet shells. The mousse may be used as a cake or pastry filling.