Soak the gelatine in cold water. Coarsely crumble about 2/3 of the Amarettini. Mix with liqueur and coffee.
Beat the egg whites and 1 pinch of salt until stiff and add icing sugar. Continue beating until the sugar has dissolved. Whip 100 g cream until stiff.
Mix the quark and vanillin sugar. Squeeze the gelatine and dissolve carefully. First stir 3 tbsp. quark into the gelatine, then stir into the remaining quark. Stir in amarettine crumbs and grated chocolate.
Fold in the egg white and cream. Rinse four moulds or cups (each containing approx. 200 ml) cold. Pour in the mixture and leave to cool for at least 4 hours.
Caramelise the sugar in a pan until golden brown. Add 100 g of cream. Boil the caramel at low heat while stirring. Let the sauce cool down.
Dip the moulds in hot water and turn the mousse onto plates. Decorate with caramel sauce and rest of Amarettini.