Peel and roughly dice the onion. Heat the fat in a pot and braise the onions while stirring. Deglaze with broth. Add peas, cured pork neck, marjoram and bay leaf. Bring everything to the boil, cover and cook over medium heat for about 1 hour.
Meanwhile clean and wash the potatoes, carrots and leek. Halve the carrots and cut the leek into 3 pieces. After about 30 minutes add potatoes and carrots to the stew and cook. Add leek 5-10 minutes later. Only add Krakow sausages in the last 10 minutes. Remove meat, krakauer, vegetables and bay leaf from the stew with a skimmer. Finely mash the peas in the stock. Remove meat from the bone. Dice meat, carrots and potatoes. Cut kielbasa and leek into slices.
Finely mash the peas in the stock. Remove meat from the bone. Dice meat, carrots and potatoes. Cut kielbasa and leek into slices. Add meat, sausage and vegetables to the pureed soup and bring everything to the boil again briefly. Season to taste with salt and pepper. Arrange the soup in deep plates and serve garnished with fresh marjoram as desired