Preheat oven to 350 degrees. Mix ingredients for patties in large bowl and then shape in 8 oval patties. Place in lightly greased baking dish. Bake for 40 minutes.
While patties are cooking, prepare gravy. Heat vegetable oil and whisk in flour. Add both soups to the mixture and continue to whisk. Add Worcestershire sauce and salt and pepper to taste. If you like your sauce thinner, just add water until desired consistency. Turn on low heat and continue to whisk occasionally.
When patties have cooked for 40 minutes, remove from oven and drain off excess grease. Cover with gravy and return to oven for an additional 10 minutes.
While continuing to bake the Salisbury steaks, heat vegetable oil in skillet and cook onions and mushrooms. Add a dash of Worcestershire sauce.
Remove Salisbury steaks and top individually with mushrooms and onions.