In a small bowl, mix 1 egg and 1 cup flour until grainy.
Add about 1/4 cup water (+/-) to the flour mixture.
Take some broth from the soup and add to the flour, egg and water mixture. Mix well. You want to warm the mix up with the broth so there are no lumps when you pour it in the hot soup.
With soup almost boiling, add flour mixture into soup a little at a time, stirring constantly.
Let simmer for another 15-20 minutes.
This is great topped with shredded cheese or croutons. Crumbled bacon would be a yummy addition as well.