Peel the onions, cut into fine cubes. Heat 1 tablespoon of oil, sauté onion cubes in it. Add sauerkraut, deglaze with wine and stock. Bring to the boil and simmer over medium heat for about 20 minutes.
In the meantime, clean and wash the bell pepper and cut into small pieces. Add the cubes to the cabbage approx. 5 minutes before the end of the cooking time.
Meanwhile, mix the mince with ajvar, egg and breadcrumbs and season well with salt and pepper. Shape the minced meat into small dumplings and fry in 2 tablespoons of oil for approx. 5 minutes until brown.
Cut the Cabanossi into slices and add to the soup with the meatballs. Let it steep for about 3 minutes. Then season the sauerkraut soup with marjoram, sugar, salt and pepper to taste.