Marinate beef with 2 tablespoons light soy sauce and 1 tablespoons tapioca starch or cornstarch for 5 to 10 minutes.
Heat wok. Add 1 tablespoons peanut oil. Add ginger, garlic and onion and stir fry for half a minute. Add beef and stir fry until meat changes colour. Remove and set aside.
Add all vegetables and stir fry until tender crisp.
Return beef to wok, add sauce, bring to a boil and mix well.