1 lb. cooked roast beef (can even use that you buy in deli counter)
2 tbsp. soy sauce or more to taste
1 1/2 tbsp. cornstarch
2 tbsp. peanut, vegetable, or corn oil
3 med. onions, peeled and thinly sliced (about 3 1/2 c. sliced)
1/2 tsp. powdered ginger

Slice meat very fine and put it in mixture of soy sauce, cornstarch, and 1 tablespoon oil. Set aside.

Heat 1 tablespoon oil in heavy skillet or wok. Add onions and cook until light golden brown. Stir in meat mixture and cook until meat is hot and sauce has thickened slightly. Serve over rice.