In a large pot, bring about 1.5 liters of water to a boil. Add the beef together with the soup vegetables and cook the meat for 1 1/2 – 2 1/2 hours until tender, depending on the quality.
Meanwhile, finely chop the onion and quarter the peeled potatoes. Lift out the softly cooked meat, let cool and cut into bite-sized cubes.
Strain the soup. In a saucepan, sauté the onions in a little butter until light. Dust with flour, stir briefly and gradually pour in soup.
Add potatoes and bay leaf and cook for about 15 minutes. Season to taste with salt and pepper.
Now add the beef cubes and the sauerkraut and cook for another 10-15 minutes. Serve in warmed plates.