Pour the cherries onto a sieve and drain them well (if necessary, also put them on kitchen paper to drain). Roughly chop the chocolate. Mix 500 g flour and baking powder in a bowl.
Add 150 g butter, 175 g sugar, 1 packet of vanillin sugar, eggs and quark and knead with the dough hooks of the hand mixer to a smooth dough. Place the dough on a floured work surface and knead again with your hands.
Roll out the dough into a rectangle (approx. 32 x 38 cm). Dust the cherries with 1 tablespoon of flour. Sprinkle cherries and chocolate on 2/3 of the dough (so that there is no filling on the last third when rolling up).
Roll up the dough from the narrow side and form into a stollen. Place diagonally on a baking tray lined with baking paper. Bake in the preheated oven (electric range: 200 °C/ convection oven: 175 °C/ gas: level 3) for 60-70 minutes.
Cover the stollen with aluminium foil after about half the baking time. Melt the remaining butter. Mix sugar, 25 g sugar and vanillin sugar. Spread the finished stollen while still hot with butter and sprinkle the sugar mixture on top.
Let it cool down.