1 1/2 lbs. flank steak
1/3 c. vinegar
1/3 c. salad oil
3 tbsp. brown sugar
3 tbsp. soy sauce
2 med. onions, sliced
1 clove garlic, crushed
1/2 tsp. coarsely ground pepper

Place steak in shallow glass dish. Mix remaining ingredients; pour over steak. Cover dish with plastic wrap. Refrigerate at least 8 hours or overnight, turning steak occasionally. Remove steak and onions from marinade. Grill steak 2 inches from medium coals until medium rare, about 6 minutes on each side. At the same time, cook and stir onions in aluminum foil pan or skillet on grill. To serve, cut meat diagonally.

Also use for shishkabobs.