Peppered beef stir-fry

Combine char siu sauce, soy sauce, shao hsing wine, garlic and pepper in a bowl. Place beef in a glass or ceramic bowl. Add half the sauce mixture. Stir to coat. Cover with plastic wrap. Refrigerate for 1 hour, if time permits.

Heat a wok over high heat. Add half the oil. Swirl to coat. Stir-fry beef, in batches, for 2 to 3 minutes or until just cooked. Transfer to a bowl. Wipe wok clean with paper towel.

Add remaining oil to wok over high heat. Swirl to coat. Add onion. Stir-fry for 1 minute or until onion has softened. Add choy sum stems and zucchini. Stir-fry for 2 to 3 minutes or until tender. Return beef to wok. Add choy sum leaves and remaining sauce mixture. Stir-fry for 1 minute or until heated through. Serve with rice.