The Great Onion Soup from Bon Appetit
Serves 4. The recipe calls for both chicken broth and beef broth, but using either one or the other will give an equally good result. The key to any goon onion soup is caramelizing, caramelizing, caramelizing!
2 tablespoons (1/4 stick) butter
3 pounds onions, sliced
1/2 teaspoon sugar
2 tablespoons all purpose flour
2 cups canned chicken broth
2 cups canned beef broth
2 tablespoons dry white wine
1 1/2 tablespoons brandy
1 1/2 teaspoons Dijon mustard
4 1/2-inch-thick French bread slices, toasted
4 1/8-inch-thick Swiss cheese slices
Melt butter in heavy large saucepan over medium heat. Add onions, sugar and pinch of salt. Cover pan and cook until onions are very soft, stirring occasionally, about 20 minutes. Increase heat to high and saute uncovered until onions are golden brown, about 10 minutes. Add flour and stir 2 minutes. Mix in chicken and beef broths, wine, brandy and mustard. Bring soup to boil, stirring frequently. Reduce heat to medium-low, cover and simmer 10 minutes. Season to taste. (Can be prepared 1 day ahead. Cover and refrigerate. Re-warm before continuing.)
Preheat broiler. Ladle soup into deep broiler-proof bowls. Top soup with bread slices, then cheese. Broil until cheese melts and begins to brown.