Salisbury Steak is so easy and a classic comfort food the whole family loves. Made from ground beef with a delicious rich mushroom gravy all in one pan!
Place the beef in a large bowl. Finely dice or grate 1/4 cup of the onion. Add the 1/4 cup onion to the ground meat. Slice the remaining onion and reserve for the gravy. Add the breadcrumbs, egg, ketchup, mustard, salt, and worcestershire.
Mix until combined and form into four oval patties about 3/4 inch thick.
In a large skillet, heat olive oil over medium-high heat. Brown the meat patties on each side about 2 minutes. Remove patties from the pan onto a plate. They will finish cooking later in the sauce if they're not done.
Add the onions and mushrooms and cook on medium-high for about 3-4 minutes or until onions are soft and mushrooms are golden brown.. Add more olive oil if needed. Add the garlic and cook for 30 seconds.
Lower the skillet to medium heat and melt the butter in the pan. Sprinkle the flour on top and cook for one minute. Slowly whisk in the beef broth. Add the ketchup, Dijon mustard, and worcestershire. Continue cooking for 4-5 minute or until mixture starts to thicken. Taste gravy and add salt and pepper as needed.
Add the patties back into the pan with the onion gravy and heat for a few minutes until patties are cooked through. Serve over mashed potatoes, egg noodles, or rice if desired. Store leftover salisbury steak in an airtight container.