1) In a deep casserole, cover and cook onions with butter, for about 5 minutes.
2) Add the stock, Worcestershire sauce and the seasonings and stir well.
3) Cover the casserole and cook for about 10 minutes (stir the contents during this process).
4) Allow the soup to stand for about 15 minutes.
5) Meanwhile, cook bread slices (uncovered) that have cheese spread on one side.