The Best French Onion Soup

Deeply caramelized onions, leeks and shallots simmered into a rich beef broth, topped with buttery croutons and broiled Gruyere.

Ingredients

• 2 tbsp extra-virgin olive oil
• 2 large onions, halved and thinly sliced (about 7 cups)
• 2 leeks, white and light green parts only, thinly sliced
• 1 cup thinly sliced shallots (about 2 large)

Kosher salt

• 5 garlic cloves, minced
• 3 tbsp tomato paste
• 1 tbsp herbes de Provence
• 1 bay leaf
• 1 cup dry red wine
• 1/4 cup sherry vinegar
• 8 cups beef stock or low-sodium broth

Freshly ground black pepper

• 1 stick (8 tbsp) unsalted butter, cut into chunks
• 12 baguette slices, cut 1/2 inch thick
• 4 oz Gruyere cheese, shredded (about 1 cup)
• Finely chopped thyme, for garnish

Directions

1. In a large enameled cast-iron pot, heat the olive oil. Add the onions, leeks, shallots and a pinch of salt and cook over medium heat, stirring occasionally, until very tender and caramelized, 40 to 45 minutes; add a splash of water if they look dry.
2. Stir in the garlic, tomato paste, herbes de Provence and bay leaf and cook until fragrant and glossy, about 3 minutes.
3. Add the wine and sherry vinegar and simmer, stirring, until reduced by half, 2 to 3 minutes.
4. Stir in the stock and bring to a boil, then simmer over medium-low heat until reduced to about 8 cups, about 45 minutes. Discard the bay leaf and season with salt and pepper.
5. Melt the butter in a large skillet and cook the baguette slices, turning once, until golden and crisp, about 2 minutes; set aside.
6. Preheat the broiler with a rack 8 inches from the heat. Set 6 ovenproof bowls on a baking sheet, ladle in the soup, top with croutons and Gruyere, and broil until the cheese is melted and browned, 1 to 3 minutes. Garnish with thyme and serve.

Notes

From Andrew Zimmern’s take on the French Onion Soup he learned at a Minneapolis bistro in 1992.