2 tablespoons Worcestershire sauce (or more to taste)
2 tablespoons olive oil, divided
2 tablespoons butter
16 ounces sliced fresh mushrooms (any kind; I like baby bellas)
1/4 cup flour
4 cups beef broth
Mix together the ground beef, chopped onion, garlic, and Worcestershire sauce. Season mixture with ground pepper and form into 4 oval patties. In a large skillet, heat 1 tablespoon of the olive oil over medium heat until hot. Cook patties approximately 6 minutes on each side, or until cooked through. Set aside and keep warm.
Pour excess grease out of skillet. Add butter and remaining 1 tablespoon olive oil to pan over medium heat. Add mushrooms and cook until soft, stirring occasionally, around 3 to 5 minutes. Add flour and stir for 2 to 3 minutes. Whisk or stir in broth, increase heat and boil until thick, around 3 to 5 minutes. Taste and add salt and/or ground pepper as needed. Spoon mushroom gravy over beef patties and serve.