In a large bowl, mix together the beef, breadcrumbs, onion, Italian seasoning, ketchup, Worcestershire sauce, egg and salt and pepper.
Form the meat mixture into 4 equal sized oval shaped patties.
Heat the olive oil in a large pan over medium high heat.
Place the patties in the pan in a single layer. Cook for 5-6 minutes on each side or until golden brown and cooked through.
Remove the meat from the pan. Place on a plate and cover with foil.
Melt the butter in the pan. Add the onion and mushrooms and season with salt and pepper.
Cook for 3-5 minutes or until vegetables have softened. Whisk in the beef broth, ketchup and Worcestershire sauce and bring to a simmer.
In a small bowl, mix the cornstarch with 2 tablespoons of cold water.
Add the cornstarch mixture to the pan and whisk until smooth. Cook for 1-2 minutes or until sauce has just thickened.
Add the meat back to the pan and spoon the gravy over the top. Sprinkle with parsley and serve.