01 -
Preheat oven to 350°F (175°C) and lightly grease a 9×13-inch baking dish.
02 -
In a large bowl, combine ground beef, breadcrumbs, egg, garlic powder, onion powder, salt, and black pepper. Mix gently until just blended, then shape into 4 to 6 oval patties.
03 -
Heat a skillet over medium heat. Sear each patty for 2 to 3 minutes per side until browned but still undercooked inside. Transfer patties to the prepared baking dish.
04 -
In a separate bowl, whisk together cream of mushroom soup, milk, and Worcestershire sauce until fully combined. Pour the sauce evenly over the hamburger steaks.
05 -
Distribute sliced onions and mushrooms evenly over the surface of the steaks and sauce.
06 -
Cover baking dish with aluminum foil and bake for 30 to 35 minutes. Uncover and bake an additional 10 minutes, until sauce is bubbling and steaks are cooked through.
07 -
Garnish with chopped fresh parsley before serving. Accompany with mashed potatoes or egg noodles if desired.