Defrost berries at room temperature. Knead butter, 75 sugar, flour, 1 egg and 1 pinch of salt first with the dough hooks of the hand mixer, then with your hands to a smooth dough. Wrap the dough in foil, chill for about 30 minutes
Mash the berries. Mix quark, mascarpone, 150 g sugar, vanillin sugar, 1 pinch of salt and lemon peel. Stir in 4 eggs one after the other. Stir in starch. Halve the cheese mixture. Stir in one half milk, in the other half berry puree
Roll out the dough on a floured work surface until round (approx. 34 cm Ø). Pour the dough into a greased springform pan (26 cm Ø) and press down at the edges. Place cheese masses alternately on top of each other with a tablespoon in the middle of the form. Last smoothing
Bake in the preheated oven (electric cooker: 175 °C/ convection oven: 150 °C/ gas: see manufacturer) for approx. 50 minutes on the bottom shelf. In the meantime, briefly heat up the jam and pass it through a sieve. Beat the egg whites until stiff, then add 150 g sugar. Continue beating until a shiny and smooth mixture is obtained. Briefly fold in the jam loosely
Remove the cake from the oven and spread the meringue on the cake, leaving about 1.5 cm free at the edges. Bake the cake at the same temperature for another 10-15 minutes. Remove the cake from the oven and let it cool on a cake rack for about 2 hours. Remove the cake from the tin
Waiting time approx. 30 minutes