Cut the beef and vegetables into bite-sized pieces.
Heat oil in a pan and stir-fry the beef.
Once the beef is cooked, add onions, bok choy, mushrooms, and other vegetables and stir-fry together.
Add soy sauce, minced garlic, pepper, and other seasonings, and stir-fry until the ingredients are cooked.
Add a little water, cover, and steam until the ingredients are tender.
Finally, add green onion and mix once more before serving.