In a bowl, mix ground beef, breadcrumbs, egg, Worcestershire sauce, garlic powder, onion powder, salt, pepper, ketchup, and Dijon mustard.
Divide the mixture into 4 equal portions and shape into oval patties.
Heat olive oil in a large skillet over medium heat. Cook the patties for 4–5 minutes per side until browned. Remove and set aside.
In the same skillet, melt butter. Add sliced onions and mushrooms, and cook for 5 minutes until softened.
Stir in beef broth, Worcestershire sauce, ketchup, Dijon mustard, salt, and pepper. Bring to a simmer.
Add cornstarch mixed with water and cook until the gravy thickens.
Return the patties to the skillet and simmer for 5–7 minutes, spooning gravy over them until fully cooked.
Serve hot with mashed potatoes, rice, or egg noodles, and drizzle extra gravy over the top.