Courtesy of James Peterson, Splendid Soups
This recipe does require a fair amount of stirring time at the stove but if you have the time, it is fairly simple. If you cook with wine, I suggest adding a generous ½ cup of red wine to the initial deglazing procedure.
2 ½ pounds onions, peeled and cut in half lengthwise
2-3 tablespoons unsalted butter
5 cups beef or chicken stock or equal measure of the both stocks
1 sachet: 3 fresh thyme sprigs, 3 parsley sprigs and 1 bay leaf (tied in a bundle)
Salt and freshly ground pepper
1 cup finely grated Gruyere or Swiss cheese
Thickly sliced French bread, toasted
Slice the onions lengthwise as finely as you can. Melt the butter in a wide, heavy-bottomed 4 quart pot and add the onions. Stir the onions every few minutes over medium heat until they soften and begin to brown, about 40 minutes. When they start to brown, pour in ¼ cup broth and turn heat to high. Stir the onions, scraping off any caramelized juices that have clung to the bottom and sides of the pan. When the broth has almost evaporated and forms a brown glaze on the bottom of the pan, add another ¼ cup broth and repeat. Continue doing this until you have used 1 cup of broth.
Add the remaining broth and the sachet to the onions and gently simmer the soup for 15 minutes. Be sure to scrape the bottom of the pot so the caramelized juices dissolve in the soup. Season to taste with salt and pepper and remove the sachet.
AT THE LAST MINUTE: Preheat oven to 400 degrees. Ladle the hot soup into deep ovenproof bowls. Sprinkle half the cheese over the soup and place a slice of toast in each bowl. Sprinkle the remaining cheese over the top. Put the bowls on a sheet pan and bake until the cheese bubbles and turns light brown, about 10 minutes.