In a mixing bowl, combine the ground beef, bread crumbs, Parmesan cheese, egg, garlic powder, onion powder, salt, and pepper. Mix well until fully combined.
Divide the mixture into 4 equal portions and shape each portion into a patty.
Heat the olive oil in a large skillet over medium heat. Add the hamburger patties and cook for about 4-5 minutes on each side until browned and cooked through. Remove patties from the skillet and set aside.
In the same skillet, add the sliced onions and mushrooms. Sauté for about 5-7 minutes until they are softened and golden.
Sprinkle the flour over the cooked onions and mushrooms, stirring constantly for 1-2 minutes until the flour is incorporated.
Gradually add the beef broth and Worcestershire sauce, stirring to combine. Bring the mixture to a simmer, allowing it to thicken for about 3-4 minutes.
Return the hamburger patties to the skillet, spooning the gravy over them. Let simmer on low heat for an additional 5 minutes to heat through.
Serve the smothered hamburger steak hot, garnished with fresh parsley if desired.