I had an abundance of onions from Mom and Ken's farm so I made this soup tonight. I used olive oil instead of butter and less than 1/4 c. I also used 1/2 beef broth and 1/2 chicken stock. This was our appetizer to some of Sebnem's Kufte and it was a glorious meal!

Found the below recipe on recipezaar #7751

1/4 cup butter
4 cups cooking onion, sliced
1 teaspoon sugar
1 tablespoon all-purpose flour
1 cup dry white wine
4 cups beef broth
1/4 teaspoon pepper
6 slices day-old French bread
2 cups swiss cheese, Grated
1/2 cup parmesan cheese, Grated
paprika

In large Dutch oven over medium heat, melt butter.
Add onions and sugar.
Cover and cook, stirring occasionally, 30 minutes or until onions are tender but not colored.
Uncover pan, increase heat slightly and continue to cook, stirring regularly until onions are rich caramel colour (10 to 15 minutes) DO NOT LET ONIONS BURN.
Stir in flour until well blended.
Gradually add wine; cook, stirring constantly, until mixture boils and thickens.
Stir in beef broth and pepper; bring to boil.
Reduce heat to low.
Cover and simmer 15 minutes.
Ladle soup into 6, 1-1/2 cup oven proof bowls.
Top each with bread slice; sprinkle with swiss cheese and parmesan cheeses and paprika.
Place bowls on jelly roll pan.
Broil until cheese melts and bubbles.