Cut the beef and cabbage into bite-sized pieces.
Prepare the marinade (soy sauce, sugar, minced garlic, sesame oil, black pepper).
Add the marinade to the beef and let it sit for 10 minutes.
Heat cooking oil in a pan and stir-fry the beef.
Once the beef is cooked, add cabbage and onion and stir-fry together.
When the cabbage softens, serve on top of rice to finish.