Prepare the Patties:In a large bowl, combine ground beef, bread crumbs, egg, Worcestershire sauce, garlic powder, onion powder, salt, and black pepper. Mix well and form into 4 equal-sized patties.
Cook the Patties:Heat olive oil in a skillet over medium-high heat. Cook the patties for about 4-5 minutes per side until browned. Remove from skillet and set aside.
Sauté Onions:In the same skillet, reduce heat to medium and add butter. Add sliced onions and cook for about 7-8 minutes until softened and golden.
Make the Gravy:Sprinkle flour over the onions and stir well to coat. Slowly pour in beef broth, whisking constantly to avoid lumps. Let it simmer for 3-5 minutes until thickened.
Combine & Finish:Return the cooked hamburger steaks to the skillet. Spoon gravy over them, cover, and let simmer for another 10 minutes until the patties are cooked through.
Serve:Serve hot over mashed potatoes or rice, garnished with parsley if desired.