In a large bowl, mix together the ground beef, egg, bread crumbs, pepper, salt, onion powder, garlic powder, and Worcestershire sauce.

Form into 8 balls, and flatten into patties.

Heat the oil in a large skillet over medium heat.

Fry the patties and onion in the oil until patties are nicely browned, about 4 minutes per side.

Remove the beef patties to a plate, and keep warm.

Sprinkle flour over the onions and drippings in the skillet.

Stir in flour with a fork, scraping bits of beef off of the bottom as you stir.

Gradually mix in the beef broth and vinegar.

Season with seasoned salt.

Simmer and stir over medium-low heat for about 5 minutes, until the gravy thickens.

Turn heat to low, return patties to the gravy, cover, and simmer for another 15 minutes.