Perfect French Onion Soup
Aged Gruyère is key to getting the traditional bubbling crust of cheese; it's rich, smooth, and melts easily.
- 1/4 cup unsalted butter plus more for the baking sheet
- 4 medium-large yellow onions about 2 lb., thinly sliced so you get about 8 cups
- Kosher salt and freshly ground black pepper
- 1 small baguette 1/2 lb., cut into 1/2-inch slices
- 2 quarts Beef Broth or Chicken Broth
- 1 bay leaf
- 2 cups grated Gruyère Cheese
Melt the butter in a 4-quart pot over medium heat.
Stir in the onions and season with 1 tsp. salt and a few grinds of pepper.
Reduce the heat to low.
Cover the pot with a lid, and cook, stirring occasionally, until the onions are very soft but not falling apart, 40 to 50 minutes.
Remove the lid raise the heat to medium high,cook, stirring often, until browned, about 10 minutes.
Meanwhile, make the baguette toasts.
Position a rack in the center of the oven and heat the oven to 350°F.
Butter a rimmed baking sheet and arrange the baguette slices on the sheet in a single layer. Bake until the bread is crisp and lightly browned, turning once, 15 to 20 minutes.
To Make the Soup
Add the broth and bay leaf to the caramelized onions and bring the soup to a boil over medium-high heat.
Reduce the heat to medium low and simmer for 10 minutes to blend the flavors.
Discard the bay leaf and season to taste with salt and pepper.
Position a rack 6 inches from the broiler and heat the broiler to high.
Put 6 to 8 broiler proof crocks on a baking sheet.
Put 2 or 3 toasts in each bowl and ladle the hot soup on top.
Sprinkle with the cheese and broil until the top is browned and bubbly, 2 to 5 minutes.