Slice the beef thinly.
Julienne the onion, carrot, and green onion.
In a bowl, marinate the beef with soy sauce, sugar, minced garlic, sesame oil, and pepper.
Heat oil in a pan and stir-fry the onion, carrot, and green onion.
Add the marinated bulgogi and stir-fry together.
Once the meat is cooked, transfer to a plate.