Chop the onion finely and sauté it in salad oil until translucent. Set aside to cool.

In a bowl, combine ground meat, beaten egg, milk, okara powder, salt, and pepper. Mix well.

Add the cooled sautéed onion to the meat mixture and mix thoroughly.

Shape the mixture into patties and pan-fry over medium heat until browned on both sides and cooked through.

In the same pan, melt butter and add soy sauce, grated garlic, and water to create the onion sauce. Simmer briefly.