Ingredients:

  Amount  Measure       Ingredient -- Preparation Method
--------  ------------  --------------------------------
   1 1/2  pounds        yellow onions -- thinly sliced
   3      tablespoons   butter
   1      tablespoon    olive oil
   1      teaspoon      salt
     1/4  teaspoon      sugar
   3      tablespoons   flour
   2      quarts        beef stock -- boiling
     1/2  cup           white wine
   6                    croutons
   1      cup           Swiss cheese -- grated
     1/2  cup           Parmesan cheese -- grated
                        salt -- to taste
                        black pepper -- to taste
                        croutons

Preparation:

Cook the onions slowly with butter and oil in a heavy bottom 5 quart covered saucepan for 15 minutes. Uncover pan, raise heat to moderate and stir in salt and sugar. Cook 30-40 minutes, stirring frequently until onions are golden brown. Sprinkle in the flour and cook, stirring, for 2 minutes. Blend in boiling beef stock. Add wine and season to taste. Simmer partially covered for 30-40 minutes, skimming occasionally. Pour into individual ovenproof soup crocks. Float the croutons on top of the soup and sprinkle with grated cheese. Broil until cheese melts and croutons brown.