Melt butter, add milk, warm lukewarm and dissolve yeast in it. Mix sugar, yeast milk and quark with a whisk. Stir in 1 egg. Add flour with 1 pinch of salt and knead with the dough hooks of the hand mixer for about 5 minutes to a smooth dough. Cover the dough and let it rise in a warm place for about 45 minutes
Divide the dough into 12 pieces of equal size and form into balls. Place the balls on 2 baking trays lined with baking paper, score them lightly crosswise and let them rise covered for another 10 minutes. Mix 1 egg with 1 tsp. milk and coat the balls with it. Sprinkle the balls on a baking tray with sugar crystals
Place an ovenproof dish with boiling water in the preheated oven (electric cooker: 175 °C/ circulating air: 150 °C/ gas: see manufacturer) and push the balls into the oven one by one, sheet by sheet. Bake for about 18 minutes until golden brown. Take out and let cool down. Dust the unspread rolls with icing sugar. Best served lukewarm with crème fraîche and jam
Waiting time approx. 1 hour