Ingredients:

  • 3 tablespoons (45 ml) unsalted butter
  • 2 tablespoons (30 ml) olive oil
  • 3 pounds (1.4 kg) yellow onions, thinly sliced
  • 1 teaspoon (5 ml) granulated sugar
  • 1/2 teaspoon (2.5 ml) kosher salt, plus more to taste
  • 1/4 teaspoon (1.25 ml) freshly ground black pepper, plus more to taste
  • 2 cloves garlic, minced
  • 1/4 cup (60 ml) dry sherry or dry white wine (optional, but highly recommended)
  • 8 cups (1.9 liters) beef broth, low sodium
  • 4 sprigs fresh thyme
  • 1 bay leaf
  • 1 baguette, sliced into 1-inch rounds
  • 2 tablespoons (30 ml) olive oil
  • 6 ounces (170 g) Gruyère cheese, shredded

Instructions:

  1. Melt butter and olive oil in the Dutch oven. Add onions, sugar, salt, and pepper. Cook over medium-low heat, stirring occasionally, until deeply caramelized and golden brown (about 45-60 minutes).
  2. Stir in garlic and cook for 1 minute. Deglaze the pot with sherry or white wine, scraping up any browned bits.
  3. Add beef broth, thyme sprigs, and bay leaf. Bring to a simmer, then reduce heat and simmer for 30 minutes, allowing the flavors to meld. Remove thyme sprigs and bay leaf before serving.
  4. Preheat oven to 375°F (190°C). Toss baguette slices with olive oil and bake until golden brown and crispy.
  5. Preheat broiler. Ladle soup into oven-safe bowls or ramekins. Top each bowl with croutons and shredded Gruyère cheese. Broil until the cheese is melted and bubbly.
  6. Serve Immediately. Watch out, it's hot!