Core and thinly slice cabbage. Place cabbage and apple slices into a heat- proof glass casserole, adding a small amount (1/8 - 1/4 cup) water. Add salt, butter and red wine vinegar. Bring to a boil, reduce heat, cover and simmer slowly for 1 1/2 hours. Stir occasionally and add liquid if required, during cooking. 6 servings.