In a large bowl, mix together the ground beef, breadcrumbs, egg, Worcestershire sauce, Dijon mustard, ketchup, and salt.

Form into four oval-shaped patties.

Heat a skillet over medium heat and add the extra-virgin olive oil.

Sear the patties for about 3–4 minutes per side until nicely browned.

Remove from the skillet and set aside.

In the same skillet, melt the butter.

Stir in the flour and cook for about 1 minute to form a roux.

Slowly whisk in the beef broth, Worcestershire sauce, ketchup, salt, pepper, and onion powder.

Stir until smooth and let it simmer until slightly thickened.

Add in the mushrooms, then simmer to thicken.

Return the browned patties to the skillet, spoon some gravy over them, and let them simmer on low heat for about 10 minutes, or until the patties are fully cooked.

Salisbury steak is best served with mashed potatoes, rice, or egg noodles.

Pour plenty of that delicious gravy on top, and dig in!