
Mix beef, panko, egg, half the Worcestershire, 1/2 tsp salt and pepper. Shape into 4 oval patties about 3/4 inch thick.
Brown the patties in a large skillet over medium-high heat, 3-4 minutes per side. Move to a plate (they will finish in the gravy).
Melt butter in the same pan, add sliced mushrooms and onion, and cook 6 minutes until soft. Sprinkle in flour and stir 1 minute.
Slowly whisk in broth and the rest of the Worcestershire. Simmer until thickened, about 2 minutes, then nestle the patties back in. Cover and simmer 8-10 minutes until cooked to 160°F.
Meanwhile make the mashed potatoes per the package. Spoon patties and gravy over the potatoes.
Photo: DinnerDrop