Wash and dice the leek, celery, carrot, and onion. Cook pork hocks, diced vegetables, salt and peppercorns in water to cover 2 to 3 hours or until tender. Avoid overcooking. Remove from water; drain well reserving vegetables and cooking liquid. Preheat oven to 425F (220C). Melt fat or shortening in an enamel lined, cast iron pan. Add drained pork hocks, cooked vegetables and a small amount of cooking liquid. Bake 30 minutes.
 Moisten meat frequently with more cooking liquid. Before meat is fully cooked, sprinkle with beer or water in which a good amount of salt has been dissolved. Add cumin to increase flavor, if desired. Serve with potato or white bread dumplings or sauerkraut salad.