Cut the beef and various vegetables (onion, carrot, potato, bell pepper, etc.) into bite-sized pieces and prepare them.
Heat some cooking oil in a pan and stir-fry the beef first.
When the beef is half cooked, add the prepared vegetables and stir-fry together.
Season with soy sauce, pepper, sugar, etc.
Continue stir-frying until all ingredients are thoroughly cooked.
Serve the finished Jappa on a plate.