Make the sauce, cut up veggies, make a cornstarch slurry and measure out veggie stock.
Heat the wok, add oil and sear the beef.
Remove the beef and add the onion and bell pepper. Cook until they pick up some color.
Add the veggie stock and bring to a boil. Add the sauce stir it in. Add the cornstarch slurry. When it's back to a boil and thickened add the beef and heat thru.
Remove to your serving dish and garnish with green onion.