In a mixing bowl, combine the ground beef, bread crumbs, milk, egg, garlic powder, onion powder, salt, and pepper. Mix until well combined.
Form the mixture into 4 equal-sized patties, about 1 inch thick.
Heat the olive oil in a large skillet over medium-high heat.
Once hot, add the hamburger steaks and cook for about 4-5 minutes on each side, or until browned and cooked through. Remove the patties from the skillet and set aside.
In the same skillet, add the sliced onions. Sauté for about 5 minutes or until they are tender and translucent.
Sprinkle the flour over the onions and stir to combine. Cook for another 1-2 minutes.
Gradually pour in the beef broth while stirring to avoid lumps. Add the Worcestershire sauce and bring to a simmer.
Return the hamburger steaks to the skillet, cover, and let simmer in the gravy for about 10 minutes, allowing the steaks to absorb some flavor.
Check for seasoning and adjust with salt and pepper if needed.
Serve the smothered hamburger steaks topped with the onion gravy. Garnish with chopped parsley if desired.