Heat the extra Sesame oil in a large pan or wok, stir fry the vegetables a few minutes until cooked but still crunchy, only adding Bok choy or spinach in the last few minutes. set aside cooked vegetables in bowl till later.
Remove vegetables from the pan and set aside in a bowl till later.
In a large bowl combine the marinade ingredients, the soy sauce, sherry, sesame oil, garlic, ginger and chill.
Combine the beef strips with the marinade ingredients
Heat the pan or wok again and stir fry the beef strips in batches over high heat.
In a jug blend cornflour, sauces and water, mix until smooth.
Add sauce mixture to the pan and heat until boiling.
Return the meat and vegetable to the pan and stir until coated in sauce and heated through.
Serve with boiled/steamed rice.