Directions:

In medium saucepan, heat oil over medium heat. Add onions; cook 3 to 4 minutes or until tender. Stir in remaining sauce ingredients. Bring to a boil. Reduce heat to low; simmer 15 minutes, stirring occasionally. Cool.

Place beefsteak and 1/2 cup sauce in shallow dish; turn to coat. Cover; refrigerate 6 to 8 hours (or overnight, if desired). Cover; refrigerate remaining sauce.

Remove steak from marinade; discard marinade. Place steak on rack in broiler pan so surface of beef is 3-inches from heat, broil 12 to 13 minutes for medium rare doneness, turning once. Meanwhile place reserved sauce in 1-cup glass measure. Microwave on HIGH 1 to 1 1/2 minutes or until hot. Carve steak into thin slices; serve with sauce.