Japanese Hamburger Steak

Instructions

1. Prepare the onions
   Heat 1 tablespoon of vegetable oil in a skillet over medium heat. Add the finely chopped onion and sauté until soft and translucent, about 5 minutes. Remove from heat and let cool completely.
2. Make the meat mixture
   In a large bowl, combine ground beef, ground pork, cooled sautéed onions, egg, panko breadcrumbs, milk, ketchup, Worcestershire sauce, 1/2 teaspoon salt, and 1/4 teaspoon black pepper. Mix gently with your hands until just combined, being careful not to overmix.
3. Shape the patties
   Divide the mixture into 4 equal portions. Shape each portion into an oval patty about 3/4 inch thick. Make a slight indentation in the center of each patty with your thumb to prevent it from puffing up during cooking.
4. Cook the hambagu
   Heat a large skillet over medium-high heat. Add 1 tablespoon vegetable oil. When hot, add the patties and cook for about 3-4 minutes on each side until browned. Reduce heat to medium-low, cover with a lid, and cook for an additional 5 minutes until patties are cooked through (internal temperature of 160°F/71°C).
5. Make the sauce
   Remove patties from the skillet and set aside. In the same skillet with the meat drippings, add red wine and deglaze the pan by scraping up the browned bits. Add soy sauce, mirin, and 2 tablespoons of butter. Simmer for 2-3 minutes until slightly thickened.
6. Serve
   Place hambagu patties on plates, pour the sauce over them, and serve immediately. Traditional accompaniments include steamed rice, mixed vegetables, or a side salad.