Combine the ground beef, breadcrumbs, Worcestershire sauce, ketchup, Dijon, salt and pepper. Mix well until combined. Form into 4-6 oval patties, about 3/4-inch thick.
Heat butter and oil in a skillet over medium-high heat. Fry patties on both sides until no longer pink in the middle. Remove from skillet.
For The Gravy:
Reduce heat to medium and add sliced onions. Stir and cook until golden brown and soft, 4-5 minutes. Add beef broth, ketchup and Worcestershire. In a small bowl, combine cornstarch and water. Stir in and cook to reduce, until thickened and bubbly.
Return patties to the gravy and spoon gravy over top. Let simmer and warm up for a couple of minutes.