Combine ground beef, Worcestershire sauce, ketchup, brown sugar, egg, breadcrumbs, mustard, seasoning salt, and black pepper in a large bowl.
Mix everything thoroughly.
Divide the mixture into equal portions and shape them into oval patties about 1-inch thick.
Heat olive oil and butter in a large skillet over medium heat.
Add patties and cook until browned on both sides.
In the same skillet, whisk together beef broth and cornstarch.
Let simmer while stirring occasionally until the gravy thickens.
Return the cooked patties to the skillet, cover with the gravy, and let simmer for another 15 minutes.