Slice the onion thinly and cut the beef into bite-sized pieces.

Heat salad oil in a frying pan over medium heat, sauté the onion until softened, then add the beef and cook until the beef changes color.

Add water and bring to a boil. Turn off the heat, add Hayashi sauce mix, and dissolve. Reheat and simmer over medium heat until the sauce thickens.

Place cooked rice in a heatproof dish, pour Hayashi sauce over it, and create a small indentation in the center. Add shredded cheese, crack an egg into the indentation, and sprinkle breadcrumbs on top. Repeat for 4 servings.