Cut the beef into bite-sized pieces and marinate it.
Wash the onion, cabbage, spinach, and mushrooms thoroughly, then slice them into bite-sized pieces.
Add oil to a pan and stir-fry the beef.
When the beef is halfway cooked, add the mushrooms and onion and stir-fry.
Add the cabbage and spinach, then stir-fry quickly.
Check the seasoning and finish.