Heat the cherry juice in a saucepan over medium heat for 1-2 minutes, stir in the marzipan mixture until dissolved, remove from heat, add the drained cherries, and refrigerate until cold.
In a bowl, whisk together the 2 egg yolks and 3 tablespoons sugar for 2-3 minutes until pale and foamy.
Fold the mascarpone and rum into the egg yolk mixture.
In a separate bowl, beat the egg white (use pasteurized eggs for food safety) until stiff peaks form, about 3-4 minutes.
In another bowl, beat the cream until stiff peaks form, about 2-3 minutes.
Gently fold the beaten egg white into the mascarpone mixture.
Gently fold the whipped cream into the mascarpone mixture.
Roughly chop the amarettini biscuits in a freezer bag.
In each serving glass, layer in this order: mascarpone mixture, cherry mixture, mascarpone mixture, chopped amarettini. Drizzle with 2 tablespoons of amaretto. Continue with: mascarpone mixture, cherries, mascarpone mixture.
Refrigerate for at least 2 hours before serving, or cover and refrigerate overnight.
Before serving, sprinkle a few whole amarettini biscuits on top as garnish.