1Add the 2 tablespoons of olive oil to a large skillet and fry the onion until opague. Add 1/2 cup of chicken stock. Cook until the liquid is reduced. Remove from pan and set aside.
2In a large bowl mix together 1/3 cup condensed french onion soup with ground beef, bread crumbs, egg, salt and pepper. Shape into 6 oval patties.
In a large skillet over medium high heat brown both sides of the patties. Pour off excess fat.
3In a small bowl blend flour and remaining soup until smooth. Mix in ketchup, water, worcestershire sauce and mustard. Pour over meat in skillet. Add carmelized onions on top. Cover and cook 20 minutes or until done. Stir occasionally.