In a bowl, combine 2 tablespoons cornstarch, 2 tablespoons water and garlic powder until smooth. Add beef and toss.

In a large skillet or wok over medium high heat, stir-fry beef in 1 tablespoon oil until beef reaches desired doneness; remove and keep warm.

Stir-fry broccoli and onion in remaining oil for 4-5 minutes. Return beef to pan.

Combine soy sauce, brown sugar, ginger and remaining cornstarch and water until smooth; add to the pan. Cook and stir for 2 minutes.

Serve over/with rice