French Onion Soup

This is also an easy recipe - although it's much easier if you get someone else to cut up the onions (they make me cry).

4 yellow onions - diced
brown in 1/4 cup butter
Add:
6 cups beef broth (I like to cook a roast in the slow cooker in several inches of water and use that for the starter for the broth. I supplement it with water and liquid bouillon.)

Serve with toasted French bread, covered with mozza cheese melted on top.