Salisbury Steak with Mushroom and Onion Gravy

Instructions

1. Place the ground sirloin in a mixing bowl. Add the egg, horseradish, 1/2 teaspoon of the Worcestershire, breadcrumbs, 1 teaspoon salt and a few grinds of black pepper. Combine well and form the mixture into 4 oval patties about 1/2 inch thick.
2. Heat a large, heavy skillet over medium-high heat. Coat the bottom of the pan with olive oil and add the beef patties. Sear for about 1-1/2 minutes per side, then continue cooking, turning often, until the patties are cooked through, 5 to 6 minutes total. Transfer to a plate and set aside.
3. Drain any excess fat from the pan and return it to the stove over medium heat. Add 1 tablespoon of olive oil along with the butter and once the butter has melted, add the onions. Season with salt and pepper and sauté until soft and translucent, 5 to 6 minutes. Add the garlic and cook just until fragrant, 1 minute longer.
4. Add the mushrooms and continue cooking, stirring often, until the mushrooms are lightly browned and the onions are caramelized, 6 to 8 minutes longer.
5. In a small bowl, whisk the flour and beef broth together until smooth to make a slurry.
6. Raise the heat on the mushroom mixture to medium-high and drizzle the slurry into the pan while stirring constantly and bring the mixture to a rapid simmer.
7. Keep stirring until the gravy thickens, then season to taste with salt and pepper and add the remaining 1/2 teaspoon of Worcestershire sauce.
8. Reduce the heat to medium and return the beef patties to the pan to reheat, turning them several times to coat with the gravy.
9. To serve, plate individual portions of mashed potatoes, top each with a beef patty, spoon some gravy on top and garnish with a sprinkling of fresh parsley.