Put beef, pork, steak sauce, bread, and egg into a food processor and chop evenly to make a mixture.
In a pan, add chopped onion, seasoned salt, and pepper, and caramelize until deep golden brown, then let cool.
Add the cooled caramelized onion to the meat mixture and knead well. Shape into a round patty, place a piece of butter in the center, and seal it inside.
Grease a pan with oil, place the patty, add water, cover, and cook as if steaming until cooked through to make the hamburg steak.
Coat the cooked hamburg steak with flour, egg wash, and breadcrumbs in order.
Deep-fry in hot oil until golden and crispy to complete the hamburg cutlet.
In the pan used to cook the hamburg, add button mushrooms, mirin, Worcestershire sauce, ketchup, and sugar, and simmer to make a special mushroom sauce with added umami.
Place warm rice in a bowl, generously pour the sauce, top with the hamburg cutlet, julienned perilla leaves, and a fried egg to complete the rice bowl.
Chop meat, bread, and egg, then mix with the brown caramelized onion that has been cooled and knead.
Shape the mixture into a round patty with butter inside, steam-fry in a pan with water, then coat with flour, egg, and breadcrumbs and fry until crispy.
Pour the sauce made by simmering mushrooms, Worcestershire sauce, ketchup, etc., over rice, and top with the hamburg cutlet and fried egg.
Cooking tips 💡
The caramelized onion must be completely cooled before mixing with the meat mixture to prevent the meat from cooking and clumping from the heat.
By placing butter in the center of the patty and steaming it with water, the butter melts inside, adding rich nuttiness and moisture.
The mushroom sauce, reminiscent of tonkatsu sauce, should be simmered in the same pan used to cook the hamburg so that the savory flavor of the meat is fully infused into the sauce.