Mix the mascarpone with the cream cheese until smooth and stir in 3 tablespoons of Amaretto, the sugar and the vanilla sugar.
Whip the cream with the cream stiffener and stir into the cream except for 5 tablespoons for decorating.
Drizzle the finished sponge cake base with 2 tablespoons of amaretto and spread the cream on the base.
Sprinkle the cake with crumbled amarettini and decorate with the remaining whipped cream.