Chop the onion finely and squeeze out the water.
In a bowl, mix the ☆ ingredients.
Mix the onion and the meat into Step 2, and knead well until the fat in the meat starts to melt and the whole thing gets sticky.
Form the meat mixture into patties. Throw the patties from hand to hand to remove any air pockets. Shape into ovals, and make an indentation in the middle of each patty.
Melt butter in a pan, and brown the patties on both sides over medium-low heat.
While the patties are browning, combine the ★ ingredients in a bowl.
When the patties are browned, add the combined sauce ingredients to the pan all at once. Coat the patties with the sauce, cover with a lid and simmer over low heat for 10-15 minutes. Flip the patties over occasionally.
Raise the heat to medium near the end to thicken the sauce.
Serve and enjoy.
Story Behind this Recipe
I wanted to make hamburger steaks simmered in sauce using ingredients that I always have in stock, so I simplified the recipe.
The chopped onions will be quite watery, so squeeze them out well. In Step 3, mix and knead the meat well until it's sticky. The hamburgers tend to burn when simmering, so flip them over occasionally and make sure they don't get burnt.