Beef & Broccoli Stir-Fry

1 lb Round steak cut crosswise (very thin slices)
½ cup water, divided
1/3 cup soy sauce
2 TBL brown sugar
3 TBL white grape juice (I've substituted vinegar and it works just the same)
1 clove garlic, crushed
1 tsp ginger
1 tsp cornstarch
3 TBL oil
4 cup broccoli
1 large onion, cut in wedges

Marinate steak in mixture of ¼ cup water, soy sauce, brown sugar, grape juice, garlic, ginger, and cornstarch at least 10 minutes. Drain well, reserving marinade. Heat oil in skillet. Add steak slices, half at a time, and stir-fry over high heat until browned. Remove from skillet, set aside. Add broccoli and onion to skillet. Stir-fry for 1 minute. Add remaining ¼ cup water. Cover and steam 3 minutes or until broccoli is crisp and tender. Return meat to skillet with marinade. Stir-fry to heat thoroughly. Serve over rice.