In a large skillet or wok
, heat half of the oil over high heat. Add onion, water chestnuts and broccoli. Cook until crisp and tender; for 4 minutes. Remove from skillet and set aside. Add remaining oil to skillet. Stir in beef and garlic. Cook until brown
ed, about 2 minutes. Add vegetable mixture back to skillet. In a small bowl, combine soy sauce, brown sugar, and add to skillet. Combine water and cornstarch to make a smooth paste. Stir into skillet. Cook until sauce thickens and heated through. Serve with rice or Oriental noodes, if desired.