Powder the biscuits finely either manually or using a food processor. Add in melted butter and mix well. Press it down firmly onto a 20" springform pan with the back of a glass. This forms the base of the mousse cake. Allow it to chill in the refrigerator to set well.
Meanwhile beat whipping cream with vanilla essence until it forms soft peaks. Fold in powdered sugar as desired. Chill it until you melt the chocolate for the mousse.
Melt chocolate with some butter in a microwave or using a double boiler method whichever suits you well. Let it cool down a bit and then slowly fold in the chilled cream.
Pour this onto the biscuit base in the pan and smoothen out. Refrigerate overnight for the best results. Since it is a no bake recipe, 8 hours mentioned here is the chilling time.
Cut into triangles and serve it super chilled the next day and see it disappearing within no time at all.
