Chocolate mousse

Heat 3/4 cup cream in a heavy saucepan until hot.

Whisk together yolks, sugar, and a pinch of salt in a metal bowl until combined well, then add hot cream in a slow stream, whisking until combined.

Transfer mixture to saucepan and cook over moderately low heat, stirring constantly.

Pour custard through a fine-mash sieve into a bowl and stir in vanilla.

Melt chocolate in a double boiler or a metal bowl set over a pan of simmering water, stirring frequently. Whisk custard into chocolate until smooth, then cool.

Beat remaining 1 1/4 cups cream in a bowl with an electric mixer until it just holds stiff peaks. Whisk one fourth of cream into chocolate custard to lighten, then fold in remaining cream gently but thoroughly.

Take a glass.Put a layer of Oreo biscuits and then cake crumbs.Pour 2 spoon of mousse and repeat it and chill,covered, at least 6 hours.

Let stand at room temperature about 20 minutes before serving.