Slowly stir the onions in the butter one hour, stirring frequently, being very careful not to brown; add salt, pepper, cayenne and stock, and cook one hour longer. Add one-third as much stock. Have in the tureen the bread and cheese. Beat up the eggs with a ladle full of soup; pour this on the bread, cover close, and stand five minutes. Add the rest of the soup and serve at once.
Attributed to Mrs. Werner.