Whip the cream until stiff and allow the vanilla sugar to trickle in. Mix ricotta, yoghurt and sugar. Stir in sauce powder, fold in cream.
Put the cookies in the freezer bag, seal it and crumble them finely with a cake roll.
Pour half of the ricotta-vanilla mousse into four dessert glasses and add the crumbled cookies, to about 1 tablespoon. Spread the rest of the mousse on top. Sprinkle with the remaining cookie crumbs, chill for about 1 hour.