beef flank or round steaks
1Each flank steak should weigh between 1 and 1 1/2 pounds.
2Place beef steaks in shallow glass or plastic dish.
3Mix remaining ingredients and pour over the beef.
4Cover and refrigerate at least 8 hours, turning occasionally.
5Set oven control to broil.
6Place beef on rack in broiler pan.
7Broil with the tops about 3 inches from the heat until brown, about 5 minutes.
8Turn beef and broil about 5 minutes longer.
9Cut beef in thin strips across the grain of the meat.
10Serve with tortillas and guacamole if desired.