Crumble Amarettini, except for a few for decoration. Separate the eggs. Beat the quark, mascarpone, milk, 100 grams of sugar, lemon rind and egg yolk with the whisks of the hand mixer until foamy.
Add semolina and stir in. Beat egg whites until stiff and fold into the mascarpone quark mixture. Fill into a greased gratin dish (approx. 24 cm Ø) sprinkled with semolina and smooth it down. Sprinkle Amarettini, except for something to sprinkle, over the top and bake in a preheated oven (electric range: 200 °C/ gas: level 3) for 45 minutes.
Cover with aluminium foil after about 15 minutes. In the meantime, pick the berries, wash and drain. Mix starch and three tablespoons of juice. Boil up the rest of the juice and sugar in a pot.
Stir in starch and bring to the boil again. Add berries and carefully fold in. Let gratin cool slightly and sprinkle with remaining amarettine crumbs and, if desired, with sugar crystals.
Cut gratin into pieces and arrange on plates with the sauce. Serve with the rest of the amarettini and, if you like, decorated with lemon balm.