Cook the plate lentils in the vegetable stock for 30 minutes, then add the finely chopped leek and diced carrots, celery, onions and potatoes. Simmer on a moderate heat for another 20 minutes. Season the lentil stew with salt, pepper, nutmeg, cayenne pepper, mustard, parsley and a pinch of sugar. Add the sliced wieners to the soup and let them get hot for 5 minutes.
Depending on your taste, season with vinegar on the plate and serve with fresh bread with butter or margarine.