Classic French Onion Soup
A deeply flavorful, comforting French onion soup with slowly caramelized onions, rich beef broth, and a golden, cheesy baguette topping broiled to perfection. Ideal as a warming starter or satisfying main course.
Equipment
- 1 large Dutch oven or heavy soup pot
- 1 Wooden Spoon
- Ovenproof soup crocks (4 to 6)
- 1 Baking Sheet
- Cheese grater
Ingredients
- 4 tablespoons unsalted butter
- 1 tablespoon vegetable oil
- 3 pounds sweet onions such as Vidalia, halved and thinly sliced
- ¾ teaspoon salt
- ½ teaspoon freshly ground black pepper
- ¾ teaspoon granulated sugar
- 1 cup dry white wine
- 2 tablespoons all-purpose flour
- 6 cups beef broth
- 1 teaspoon Worcestershire sauce
- ½ teaspoon dried thyme
- 2 bay leaves
- 1 small baguette sliced into ½-inch rounds
- 1 tablespoon dry sherry
- 8 ounces Gruyère cheese shredded (about 2 cups)
- ½ cup grated Parmigiano Reggiano cheese
Instructions
- Caramelize the Onions: In a large heavy-bottomed pot or Dutch oven, melt the butter over medium heat. Add the vegetable oil, then toss in the sliced onions along with salt, pepper, and sugar. Cook the onions uncovered, stirring occasionally at first. As the onions begin to soften and turn golden, stir more frequently to prevent sticking or burning. The goal is a deep golden brown and richly caramelized onion base, which usually takes about 45 to 55 minutes. If the onions start to stick or brown too fast, lower the heat or splash a little water to deglaze the pan.
- Deglaze and Reduce with Wine: Raise the heat to medium-high and pour in the white wine. Use a wooden spoon to scrape up any browned bits from the bottom of the pot. Let the wine simmer and reduce until nearly evaporated and the onions become jammy, about 8 to 10 minutes.
- Thicken the Base: Sprinkle the flour evenly over the onions and stir continuously for about one minute to cook the raw flour taste out. This helps thicken the broth later.
- Add Broth and Herbs: Pour in the beef broth, then add Worcestershire sauce, dried thyme, and bay leaves. Stir everything to combine, bring the soup to a boil, then reduce to a gentle simmer. Cover the pot and let it cook for 30 minutes, allowing the flavors to meld beautifully.
- Prepare the Toasted Bread: While the soup simmers, preheat your oven to 400°F (200°C). Arrange the baguette slices in a single layer on a baking sheet. Bake for about 10 minutes or until they are dry, crisp, and slightly golden around the edges. Set aside.
- Finish the Soup Flavor: Once the simmering is complete, remove and discard the bay leaves. Stir in the dry sherry, then taste and adjust seasoning as needed. Add a splash more Worcestershire sauce for depth or a pinch of sugar if the soup needs a touch more sweetness.
- Assemble and Broil: Position an oven rack about 6 inches from the broiler and preheat the broiler. Ladle the hot soup into oven-safe crocks or bowls. Top each serving with one or two toasted baguette slices, making sure not to overlap. Sprinkle a generous layer of Gruyère and Parmigiano Reggiano cheeses on top. Place the crocks on a baking sheet and broil until the cheese melts, bubbles, and develops golden edges, approximately 3 to 5 minutes.
- Serve Carefully: Remove the crocks from the oven and allow them to cool slightly before serving to avoid burns. Enjoy your rich, comforting French onion soup!
Notes
Make-Ahead Tip: You can prepare the soup base up to three days in advance and refrigerate it (without the toasted bread or cheese). The soup also freezes well for up to three months. Reheat gently on the stove before assembling and broiling.
Toasts: The toasted baguette slices can be made a day ahead and stored in an airtight container at room temperature without cheese. Add the cheese and broil just before serving for best texture.
No Ovenproof Crocks? Use regular bowls for serving the soup, and place the cheese-topped toasts separately on a baking sheet under the broiler until bubbly and golden. Then top each bowl of hot soup with a cheesy toast.
Onion Variety: Sweet onions like Vidalia or Walla Walla offer natural sweetness ideal for caramelization, but yellow onions work well too.
Adjusting Thickness: If you prefer a thicker soup, increase the flour slightly or reduce the broth by simmering longer before adding the final touches.
