Knead 300 g flour, 125 g sugar, 1 pinch of salt, vanilla sugar, 200 g soft butter and egg yolk first with the dough hooks of the hand mixer, then briefly with your hands to form crumbles
Mix 750 g flour and baking powder in a bowl and make a depression in the middle. Add eggs, 175 g sugar, 2 packets of vanilla sugar and 1 pinch of salt to the hollow and mix with some flour from the edge to a thick paste. Cut 180 g cold butter into cubes and add to the mash together with the quark. Knead first with the dough hooks of the hand mixer, then with your hands to a smooth dough
Halve the dough and roll out one half to a rectangle (approx. 38 x 40 cm) on a lightly floured work surface. Mix mascarpone and 4 sachets of vanilla sugar until smooth. Spread half of the mascarpone evenly on the dough, leaving an approx. 2 cm wide rim on the two short sides. Stir the jam briefly and spread half of it on the mascarpone cream. Roll up the dough from one short side
Cut the roll of dough with a long, sharp knife into 14-15 approx. 2.5 cm wide slices, wiping the knife with a damp cloth in between. Place slices in rows next to each other with the cut surface facing upwards on a greased fat pan (approx. 32 x 39 cm) sprinkled with breadcrumbs. Process the second half of the dough in the same way and place it in the fat pan. Sprinkle with crumbles and bake in a preheated oven (electric range: 175 °C/ convection oven: 150 °C/ gas: level 2) for approx. 50 minutes. Let the rose crumble cake cool down in the fat pan on a cake rack. Dust with icing sugar as desired. Whipped cream tastes good with it