In a large bowl, mix the ground beef, egg, Worcestershire sauce, Dijon mustard, minced garlic, breadcrumbs, onion powder, salt, and pepper until just combined. Avoid overmixing to keep the patties tender.

Divide the mixture into four equal portions and shape them into oval patties, ensuring they are of even thickness for consistent cooking.

Heat olive oil in a skillet over medium-high heat. Add the patties and cook for 5–6 minutes on each side, or until they are beautifully browned. Transfer to a plate once done.

In the same skillet, add the sliced onion and mushrooms. Cook for 7–9 minutes, stirring occasionally, until they are golden and tender, releasing their delicious flavors.

Reduce the heat to medium. Melt the butter in the skillet, then stir in the flour and cook for 1–2 minutes until it’s bubbly, forming a roux for the gravy.

Gradually whisk in the beef broth until the mixture is smooth. Stir in Worcestershire sauce and garlic powder, enhancing the savory taste of your gravy.

Return the cooked patties, along with the mushrooms and onions (with their juices), to the skillet. Let them simmer for 5–7 minutes until the patties are fully cooked and the gravy thickens to a luscious consistency.

Plate your Salisbury steaks with a generous ladle of gravy over the top. These taste delightful alongside creamy mashed potatoes or buttered noodles!