Soupe a l’Oignon Gratinee
There are about as many different versions of this soup as there are bistros in Paris; some (like this one) add a drop of flour to thicken the broth, some (like this one) add a sprinkling of sugar to hasten the caramelization. From that point, its preparation becomes a balancing act between beefiness, sweetness, and the necessity of a high note to brighten up the often murky flavors. My secret: a splash of Banyuls vinegar.
2 tablespoons clarified butter
5 medium onions, peeled and sliced thinly into rounds
1 tablespoon sugar
1 cup dry red wine (I used a Cote du Luberon)
1 tablespoon all purpose flour
2 sprigs fresh thyme
6 cups strong beef stock
salt, to taste
1/2 teaspoon black peppercorns, lightly crushed
1/2 tablespoon of Banyuls (or other sweet red wine vinegar)
4 baguette slices, toasted
Gruyere, grated, as much or as little as you prefer
1. In a heavyweight, four quart sauce pan set over medium heat, melt the butter. Add the onions and toss well. Reduce the heat to low, sprinkle with sugar and stir, cover, and let cook down slowly, until the onions take on a golden, caramel color and are slightly jammy in consistency, about 15 minutes.
2. Pour in the wine, raise the heat to medium, stir, and let simmer for about five minutes, until the wine just begins to evaporate. Sprinkle in the flour, give the mixture a stir to combine, and add the thyme. Stir in the stock, taste for salt, and add the pepper. Simmer for five minutes, then reduce the heat to medium low, and cook uncovered for 15 minutes, stirring occasionally. Add the vinegar, stir, continue to cook over low heat for another five minutes, and remove from heat.
3. Preheat your broiler. Set two deep soup bowls onto a rimmed baking sheet. Ladle the soup into the bowls, stopping about half an inch from the rim. Float the two baguette toasts in each bowl, and then top with the Gruyere. Broil until golden and bubbling, and serve immediately.