Mix 150 sugar and 300 g flour in a bowl. Add 200 g butter in flakes and quickly work into crumbles with the whisk of the hand mixer. Put the crumbles in a cool place.
Mix 400 g flour, 50 g sugar, vanillin sugar and salt in a bowl. Melt 60 g butter in a saucepan, add 200 ml milk. Dissolve yeast in the lukewarm mixture, pour into the flour mixture.
Add the egg and knead everything with the dough hook of the hand mixer for about 4 minutes. Cover and leave to rise in a warm place for about 45 minutes.
Cut the vanilla pod in half lengthwise and scrape out the pulp. Mix quark with 30 g sugar, starch, egg yolk and vanilla pulp. Wash the grapes, dab dry and cut in half. Peel, clean and quarter apples and remove core.
Cut apples into small cubes and sprinkle with lemon juice.
Line 2 baking trays with baking paper. Roll out the yeast dough on a floured work surface approx. 4 mm thin and cut out approx. 15 circles (each approx. 10 cm Ø). Cover the dough circles again and let them rise for 15-20 minutes.
Put 2-3 tablespoons of quark mixture on each circle, spread apple cubes and grapes on top, sprinkle with crumbles. Bake in a preheated oven (electric cooker: 200 °C/ circulating air: 175 °C/ gas: see
manufacturer) bake for about 20 minutes.
Let the baked pastry cool down on a cake rack. Melt the chocolate over a warm water bath and fill it into a piping bag with a small perforated nozzle. Decorate crumbled particles with it.
Allow to dry.