1/2 c. vinegar
2 tbsp. cooking oil
2 tsp. chili powder
1/8 tsp. pepper
1/2 c. catsup
2 tbsp. onion, finely chopped
1 tsp. salt
3 lbs. beef chuck steak, 1/2 inch thick

Combine first 7 ingredients. Slash fat edges of meat. Place in shallow dish. Pour vinegar, catsup mixture over steak. Let stand 3 hours at room temperature or overnight in refrigerator, turning steak several times. Drain steak, reserving marinade; pat dry with paper towels. Cook over hot coals about 20 minutes on each side for rare; or 25 minutes on each side for medium. Brush occasionally with reserved marinade.