Preheat broiler. To prevent smoking, add 1/2 inch of water to broiler pan and set aside. In a small bowl, combine rosemary, oil, mustard and pepper. Brush mixture onto both sides of the lamb chops.Place chops on prepared, unheated broiler pan. Broil about 4 inches from heat, 7 to 11 minutes, or until desired doneness, turning once. Serve immediately. Yields 4 servings.