Fill crushed amaretti cookies into a wide decorative glass bowl.
Measure out creme de cassis and reserve 4 tablespoons. Mix remaining creme de cassis with frozen raspberries in a bowl and layer on top of the amaretti cookies.
Combine mascarpone cheese, cream, and reserved 4 tablespoons cassis in a bowl and beat until creamy. Mix in vanilla sugar. Carefully spread mascarpone cream on top of the raspberries using a spatula, keeping the raspberry layer intact.
Cover well with plastic wrap and refrigerate at least 4 hours or overnight. Remove 30 minutes before serving and garnish with chocolate.
