01 -
In a large bowl, combine the beef, breadcrumbs, egg, Worcestershire sauce, salt and pepper, using your clean hands. Divide into 6 equal pieces and form each one into oval patties.
02 -
In a large skillet add the olive oil and butter and heat until melted over medium-high heat. Add the meat patties and fry on both sides until no longer pink in the middle, about 5 minutes per side. Transfer the patties to a plate.
03 -
Reduce the heat to medium and add the sliced onions and cook until softened, about 3 to 5 minutes.
04 -
Add the mushrooms and cook for a few more minutes until the onions are golden brown, another 3 minutes.
05 -
Add the beef broth, tomato paste, soy sauce, and Worcestershire sauce and stir. In a small bowl whisk the cornstarch with a bit of water or beef broth and add to the skillet. Whisk until the sauce thickens, for about 2 minutes.
06 -
Add the meat back to the pan and spoon gravy over the top. Cook for another minute until the meat patties warm through. Garnish with parsley and serve over mashed potatoes.