01 -
Start by preheating your oven to 350°F (175°C). Grease a 9×13-inch baking dish and set it aside.
02 -
In a mixing bowl, combine the ground beef, breadcrumbs, egg, garlic powder, onion powder, salt, and pepper. Mix everything together until just combined. Shape the mixture into 4-6 oval patties.
03 -
Heat a skillet over medium heat. Sear each patty for 2-3 minutes on each side until browned but not fully cooked. Transfer the patties to the prepared baking dish.
04 -
In a bowl, whisk together the cream of mushroom soup, milk, and Worcestershire sauce until smooth. Pour this mixture over the hamburger steaks in the baking dish. Scatter the sliced onions and mushrooms (if using) over the top.
05 -
Cover the baking dish with foil and bake for 30-35 minutes. Remove the foil and bake for an additional 10 minutes, or until the sauce is bubbly and the steaks are cooked through.
06 -
Garnish with fresh parsley if desired, and serve warm with mashed potatoes or egg noodles.