Peas peel and wash. Peel and wash potatoes and cut them into pieces. Heat the fat in a pot and steam the potatoes and peas for 3-5 minutes. Season with salt and pepper. Deglaze with 1/2 litre stock, bring to the boil and cook for about 10 minutes at low heat. Remove about half of it and puree it with a blender. Peel, wash and slice the carrots.
Put them into the pot together with the pureed soup and the remaining stock. Bring to the boil again and cook over low heat for another 5 minutes. Cut the sausages into slices. Wash marjoram, dab dry, pluck leaves from the stalk and add to the soup together with the sausage slices shortly before the end of the cooking time. Add crème fraîche and mix. Season soup again. Serve garnished with parsley as desired