1-Let’s dive into making this Salisbury steak, starting with gathering your ingredients to keep things smooth. Begin by mixing the ground beef with panko breadcrumbs, a beaten egg, ketchup, Dijon mustard, dried oregano, and kosher salt in a large bowl until just combined. This step ensures the patties hold together without becoming tough.

2-Next, shape the mixture into four oval patties, each about 3/4-inch thick, for even cooking. Heat the olive oil in a large nonstick skillet over medium-high heat and cook the patties for about 3 minutes per side until they get a nice golden crust, then set them aside on a plate. Now, reduce the heat to medium and add butter to the skillet with the drippings; once it’s melted, whisk in the flour until smooth.

3-Lower the heat to medium-low and gradually whisk in the beef stock, ketchup, Worcestershire sauce, and onion powder, then stir in the sliced mushrooms. Let this simmer for about 5 minutes until the gravy thickens, and season with salt and pepper. Finally, return the patties to the skillet, nestle them in the gravy, cover, and cook for another 10 minutes until they reach an internal temperature of 160°F. Serve them over mashed potatoes with a generous spoonful of that mushroom gravy on top.