Ingredients:

  • 4 boneless, skinless chicken breasts (about 6 oz/170g each)
  • 1 tablespoon olive oil (15ml)
  • Salt and freshly ground black pepper, to taste
  • 2 large yellow onions, thinly sliced (about 2 lb/900g)
  • 2 tablespoons unsalted butter (30g)
  • 1 teaspoon granulated sugar (5g)
  • 1/2 teaspoon dried thyme (2.5ml)
  • 1/4 cup dry white wine (such as Sauvignon Blanc or Pinot Grigio) (60ml) - Optional
  • 4 cups beef broth (950ml)
  • 1 tablespoon Worcestershire sauce (15ml)
  • 4 slices of crusty bread (baguette works great!)
  • 1 cup shredded Gruyère cheese (about 4 oz/115g)
  • Fresh parsley, chopped, for garnish (optional)

Instructions:

  1. Season chicken breasts with salt and pepper.
  2. Heat olive oil in the skillet over medium-high heat. Sear chicken breasts for 2-3 minutes per side, until lightly browned. Remove from skillet and set aside.
  3. Add butter to the skillet. Add sliced onions, sugar, and thyme. Cook over medium heat, stirring occasionally, for 20-25 minutes, or until the onions are deeply caramelized and golden brown.
  4. If using, pour in the white wine and scrape up any browned bits from the bottom of the pan. Add beef broth and Worcestershire sauce. Bring to a simmer and cook for 5 minutes. Taste and adjust seasoning if needed.
  5. Arrange the seared chicken breasts in the baking dish. Ladle the French onion mixture over the chicken. Top each chicken breast with a slice of bread.
  6. Sprinkle Gruyère cheese evenly over the chicken and bread.
  7. Bake in a preheated oven at 375°F (190°C) for 15-20 minutes, or until the cheese is melted, bubbly, and lightly golden brown, and the chicken is cooked through (internal temperature reaches 165°F/74°C).
  8. Garnish with fresh parsley (if desired) and serve immediately.