Clean and wash the bell peppers, cucumber and radishes. Cut radishes into slices, except for a few for garnishing. Dice paprika and cucumber finely. Stir curd, horseradish and mineral water until smooth. Season with salt. Stir in vegetables, except for 2 tablespoons. Clean, wash and drain the salad.
Wash dill as well, dab dry and cut finely. Wash, peel and coarsely grate the potatoes. Stir in eggs and flour and season with salt and pepper. Heat some oil in a pan and fry 4 large Rösti one after the other. Arrange Rösti with salad and quark on 4 plates and sprinkle with dill and pepper. Serve garnished with remaining radishes