Knead the flour, 1 tablespoon of sugar, 1 packet of vanillin sugar, salt, 125 g of curd cheese and butter in pieces, first with the dough hooks of the hand mixer, then with your hands to a smooth dough. Cover and chill for about 30 minutes.
Grease a tart mould (24 cm Ø) with lift-off base. Roll out the dough round (approx. 28 cm Ø) on a work surface dusted with flour. Line the mould with the dough, press it down and cut off any protruding edges. Prick the dough base several times with a fork and refrigerate for another 30 minutes.
Mix 150 g quark, buttermilk and egg, sauce powder, 1 tablespoon sugar, 1 packet vanillin sugar and stir into the buttermilk quark. Wash and sort blackberries. Peel apples, use an apple corer to cut out the core. Cut the apples in half and scratch the round sides several times with a small knife
Pour the glaze into the tart and cover with the apple halves. Place the blackberries in the gaps and bake in a preheated oven (electric range: 175 °C/ convection oven: 150 °C/ gas mark 2) for approx. 1 1/4 hours
Remove the tart and let it cool on a cake rack. Bring the jam to the boil with 1 tsp. water and spread the tart. Whipped cream tastes good with it
waiting time approx. 2 hours