In a large bowl, combine ground beef with breadcrumbs, seasonings, egg, worshtershire sauce and ketchup. Form mixture into four evenly sized patties.
Heat olive oil in a large skillet over medium heat. Cook patties until browned on both sides. Remove from skillet and melt butter in the skillet.
Cook mushrooms and sliced onions until softened. Add in flour and let cook for a minute to brown. Add in beef broth and, let simmer for a couple of minutes, until the mixture has thickened.
Add beef patties back into skillet and let them heat through.
