1 Tbsp unsalted butter
3 pounds yellow onions (about 6 medium) thinly sliced
5 cups beef broth, preferably homemade
1/2 cup apple juice
1 1/2 tsp kosher salt, plus more to taste
freshly ground pepper to taste
1 Tbsp Cognac
8 to 12 1/4-inch thick slices French baguette, depending on the diameter of the loaf
1/4 pound Gruyere cheese, grated
Melt the butter in a large heavy skillet over medium-high heat. Add the onions and cook, stirring often until caramelized and very soft, about 30 minutes. Place in a large saucepan. Add the broth, apple juice and 1 1/2 tsp salt and pepper.
Bring to a boil, lower the heat and simmer for 30 minutes. Stir in the Cognac. Taste, and add more salt if needed.
Just before serving, preheat the broiler.
Reheat the soup if necessary and ladle into 4 large ovenproof bowls. Cover each with the bread, sprinkle with cheese and broil until melted and just beginning to brown, about 2 minutes.
Carefully removed from oven and served immediately.
Yield: 4 servings.
