Crumble the yeast and dissolve with sugar in 100 ml of lukewarm water. Put the flour in a bowl and make a depression in the middle. Pour in the yeast mixture. Mix with some flour from the edge to the pre-dough and let it rise covered in a warm place for about 20 minutes
Squeeze the sauerkraut well and chop coarsely. Fry the ham in a pan without fat. Steam sauerkraut and caraway for about 5 minutes. Cooling
Add approx. 300 ml lukewarm water, sauerkraut and salt to the pre-dough and knead everything with the dough hooks of the hand mixer to a tough dough. Cover and leave to rise for approx. 30 minutes
Knead the dough again, cut in half and form 2 round loaves. Leave to rise for approx. 30 minutes on a baking tray lined with baking paper. Then bake in a preheated oven (electric cooker: 200 °C/ convection oven: 175 °C/gas: level 3) for 50-60 minutes (for a nice crust, place a bowl with water on top). Let the bread cool down
Cut the cheese into small pieces. Peel and chop onion. Knead both with quark and butter, season with salt and pepper. Wash and finely chop the chives and sprinkle them over the onion. Serve with bread