Cut the beef into bite-sized pieces.
Slice the onion thinly.
Beat the eggs in a bowl.
Heat cooking oil in a pan and stir-fry the beef.
When the beef is cooked, add the onion and stir-fry together.
Season with soy sauce, salt, and pepper when the ingredients are cooked.
Pour in the eggs and cook on low heat.
Serve the beef and eggs over rice to complete the dish.