Peel and wash the potatoes. Cook in boiling broth for 15-20 minutes. In the meantime defrost the peas. Clean, wash and cut the leek into rings. Cut the sausages into diagonal slices.
Heat the fat. Fry the leek for approx. 5 minutes, turning it over. Add the leek and peas to the potatoes 5 minutes before the end of the cooking time. Then stir in the sour cream. Sprinkle with sauce thickener, bring to the boil briefly.
Briefly fry the sausages in the leek fat and mix into the ragout. Season to taste with salt, pepper and nutmeg. Wash and chop the parsley and sprinkle over it.