Trim excess fat from steak; cut steak into 10 serving-size pieces. Melt shortening in large skillet, and brown steak on each side. Remove meat to a 2 1/2- quart shallow baking dish; set aside. Reserve pan drippings in skillet.
Sauté onion in reserved drippings until tender. Set aside.
Combine catsup, water, vinegar, sugar, Worcestershire sauce, mustard, salt, and pepper. Add catsup mixture to sautéed onion in skillet. Mix well. Simmer 5 minutes, stirring often.
Pour sauce over steak in baking dish. Cover and bake at 350° for 1 hour or until steak is tender. Remove meat to a serving platter. For a "blue ribbon" dish, garnish with parsley and spiced apple rings topped with a lemon slice and a maraschino cherry half, if desired.