Dice the onion and paprika and drain the sauerkraut. Heat the oil in a pan, fry the potato noodles for about 5 minutes until golden brown, remove and set aside. Briefly fry the onion cubes in the same pan, add the tomato paste and sweat and then add the paprika cubes and the sauerkraut as well. Season to taste with the spices, pour in the stock and stew with the lid closed for about 10 minutes. Mix in the potato noodles at the end, reheat briefly and add 1 tablespoon of sour cream to the food to serve.