Ingredients:

  • 2 tablespoons unsalted butter (28g)
  • 2 tablespoons olive oil (30ml)
  • 3 large yellow onions, thinly sliced (approx. 900g)
  • 1 teaspoon granulated sugar (5g)
  • 1/2 teaspoon dried thyme (1g)
  • 1/4 teaspoon freshly ground black pepper (0.5g)
  • 1/4 teaspoon salt (1.5g)
  • 6 cups beef broth (1.4L) - low sodium preferred
  • 1/2 cup dry red wine (120ml) - such as Burgundy or Cabernet Sauvignon (optional)
  • 1 tablespoon Worcestershire sauce (15ml)
  • 1 bay leaf
  • 6 slices baguette, about 1/2 inch thick
  • 2 cups shredded Gruyère cheese (approx. 200g)

Instructions:

  1. Melt butter and olive oil in a large pot. Add onions, sugar, thyme, salt, and pepper. Cook over medium-low heat, stirring occasionally, until deeply golden brown and caramelized. This takes time; be patient and avoid burning.
  2. If using, add red wine to the pot and scrape up any browned bits from the bottom. Cook until the wine is mostly evaporated.
  3. Add beef broth, Worcestershire sauce, and bay leaf. Bring to a simmer, then reduce heat and simmer for at least 30 minutes, or up to an hour, to allow the flavors to meld. Taste and adjust seasonings as needed.
  4. Preheat oven to 350°F (175°C). Arrange baguette slices on a baking sheet and lightly toast for a few minutes per side, until slightly crisp. Watch carefully to prevent burning.
  5. Ladle soup into oven-safe bowls or ramekins. Top each bowl with a toasted baguette slice and a generous amount of Gruyère cheese.
  6. Place bowls on a baking sheet and broil in the oven until the cheese is melted, bubbly, and lightly browned. Keep a close eye on it; broiling can go from perfect to burnt in seconds!
  7. Let cool slightly before serving.