In a large bowl, combine ground beef, bread crumbs, egg, Worcestershire sauce, salt, and black pepper. Mix until well combined. Shape mixture into 4 oval patties.
In a large skillet, heat olive oil over medium-high heat. Add the patties and cook for 5-6 minutes on each side, or until well browned. Remove from skillet and set aside.
In the same skillet, reduce heat to medium and add onions and mushrooms. Cook until onions are translucent and mushrooms are tender.
Sprinkle flour over the onions and mushrooms, stir, and cook for another 1 minute.
Add beef broth, ketchup, mustard powder, and garlic powder to the skillet. Stir until the mixture begins to thicken.
Return patties to the skillet and spoon the gravy over them. Cover and simmer for 15-20 minutes.
Serve hot, garnished with fresh parsley if desired.
Notes
This recipe is a hearty and satisfying dish perfect for family dinners. Pair it with mashed potatoes or steamed vegetables for a complete meal.