In a large bowl, combine the ground beef, bread crumbs, chopped onion, egg, Worcestershire sauce, salt, and pepper. Mix until well combined but don’t overmix to keep them tender.

Form the mixture into oval patties, about 1/2 inch thick.

In a large skillet over medium heat, add a bit of oil and sear the patties for about 4 minutes on each side until they are golden-brown.

Remove the patties from the pan and set aside.

In the same skillet, add olive oil and sliced mushrooms. Sauté until tender and juices are released, about 5 minutes.

Sprinkle the flour over mushrooms, stirring until coated. Gradually whisk in the beef broth, garlic powder, onion powder, and a pinch of salt and pepper. Bring to a boil, then reduce to a simmer.

Return the seared patties to the skillet, cover, and let simmer in the gravy for another 10 minutes.

Serve the Salisbury steak with mushroom gravy over mashed potatoes, rice, or egg noodles.