Bob & Peggy's Onion Soup

10 sweet onions medium sliced (Onions will cook down a lot!)
Saute in a couple of TBS of butter and 1 cup creme sherry (more if needed to quote Bob)
Simmer on low heat for 4 hours, adding more liquid if needed
2 large cans of beef broth or vegetable broth added to sauted onions after long simmer
Slow simmer again for another hour or more adding more sherry or broth if more liquid is needed. If soup tastes too strong, water can also be added.
Do not add salt, enough is in the broth
This can all be done in a crock pot to if easier. Longer the simmer, the better the soup!
Serve in micro wave bowls with toasted french bread on bottom of bowl, add soup, and finish with a slice of swiss or provolone cheese. Micro till cheese bubbles.
I think this soup could be made without the cooking sherry, just adding more broth.