Crush oreo biscuits, pour on a casserole and keep aside.
Beat whip cream till peaks are formed fold in condensed milk, vanilla essence and gelatine mix well. Keep the cream in freezer.
For mocha mousse can use mocha custard, (boil 2 cups milk with, little sugar, 2 tablespoon cocoa powder, 1 teaspoon Coffee powder and 3 tablespoon custard powder, stir it when it boils remove from flame and cover it, whisk it well when you pour in the casserole).