Mix the ground beef, egg, bread crumbs, Worcestershire sauce, seasoned salt, onion powder, garlic powder and pepper together. Divide into 6 equal portions. Roll into an oval, then flatten. You can do this ahead of time and refrigerate if you'd like.

Heat the oil in a large skillet and fry the hamburger steaks about 4 minutes per side, until done to your liking. Remove them to a plate and keep warm.

Add the onions to the drippings and cook about 10-20 minutes, depending on how you like your onions or how much of a hurry you're in. Sprinkle the flour over the onions and stir, scraping up any bits of beef from the pan. Stir in the broth, sherry and seasoned salt. Bring to a simmer and cook about 5 minutes, until the gravy is thickened to your liking.

Turn the heat to low and add the hamburger steaks back to the pan. Cover the pan and cook simmer 15 minutes, then serve.