French onion soup is my all time most favorite soup. When I was a kid it was because of all of the cheese on top, now I really just love the rich flavor of the broth. (the cheese is still great though)
This soup did take a little bit of time to make but it wasn't hard at all and the broth freezes really well.
French Onion Soup [Soupe à l’Oignon]:
(Smitten Kitchen; Adapted from Mastering the Art of French Cooking)
1 1/2 pounds (about 5 cups) thinly sliced yellow onions
3 tablespoons unsalted butter
1 tablespoon olive oil
1 teaspoon table salt, plus additional to taste
1/4 teaspoon granulated sugar
3 tablespoons all-purpose flour
2 quarts (8 cups) beef stock
1/2 cup dry white wine or dry white vermouth
Freshly ground black pepper
Cheesy Top (Not Optional):
1 tablespoon grated raw onion
1 to 2 cups (to taste) grated Swiss (I often use Gruyere) or a mixture of Swiss and Parmesan cheese
1 tablespoon butter, melted
12 to 16 1-inch thick rounds French bread, toasted until hard
Melt the butter and oil together in the bottom of a 4- to 5-quart saucepan or Dutch oven over moderately low heat. Add the onions, toss to coat them in oil and cover the pot. Reduce the heat to real low and let them slowly steep for 15 minutes.
After 15 minutes, uncover the pot, raise the heat slightly and stir in the salt and sugar. Cook onions, stirring frequently, for 30 to 40 minutes until they have turned an even, deep golden brown.
After the onions are fully caramelized, sprinkle them with flour and cook, stirring, for 3 minutes. Add the wine in full, then stock, a little at a time, stirring between additions. Season to taste with salt and pepper. Bring to a simmer and simmer partially covered for 30 to 40 more minutes, skimming if needed.
Preheat oven to 325. Arrange six ovenproof soup bowls or crocks on a large, foil-lined baking sheet. Bring the soup back to a boil and divide among six bowls. To each bowl, add 1/2 teaspoon grated raw onion and a tablespoon of grated cheese. Stir to combine. Dab your croutons with a tiny bit of butter and float a few on top of your soup bowls, attempting to cover it. Mound grated cheese on top of it; how much you use will be up to you.
Bake soups on tray for 20 minutes, then preheat broiler. Finish for a minute or two under the broiler to brown the top lightly.