French Onion Soup

Julia requested that I post this one, but it actually comes from the Joy of Cooking so I can't take credit for it:

1 1/2 cups sliced onions
3 T butter
6 C Beef of Chicken bouillion (I just used the cubes and water)
fresh ground pepper
dash of cognac or sherry (i think this is optional, I've never had a bottle of one of these in my life!)
6 slices toasted french bread
1 cup mixed grated swiss and whatever other cheese you want to use, I used some cheddar.
sprinkle of parmesan

Saute the onions in the butter until they're very brown but not burnt. Add the broth and a dash of fresh pepper. Simmer for 30 minutes. Put the soup into a casserole dish and you can add the sherry now if you have it Cover it with the bread (I just used store bought croutons which was Yazmin's idea), and then the cheese. Sprinkle some parmesan cheese on top. Heat it in the oven at 275 degrees until the cheese on top is bubbly.

It's not very original I know, but I get cravings for this sometimes!