Ingredients:

  • 1.5 lbs boneless skinless chicken breasts, trimmed
  • 3 large yellow onions, thinly sliced (approx. 900g)
  • 2 tbsp extra virgin olive oil
  • 1 tbsp grass-fed butter
  • 0.5 tsp sea salt
  • 0.5 tsp cracked black pepper
  • 3 cloves garlic, minced
  • 1 tbsp balsamic vinegar
  • 0.25 cup dry sherry
  • 1 cup low-sodium beef bone broth
  • 1 tsp fresh thyme leaves
  • 1 cup shredded Gruyère cheese
  • 0.25 cup freshly grated Parmesan
  • 4 thin slices whole-grain baguette

Instructions:

  1. In a large oven-safe skillet over medium heat, melt the olive oil and butter. Add the sliced onions and salt. Sauté for 20–25 minutes, stirring occasionally, until they reach a deep mahogany, jammy consistency.
  2. Add the minced garlic to the onions and cook for an additional 2 minutes until fragrant.
  3. Push the onions to the edges of the skillet. Increase heat to medium-high. Season the chicken breasts with black pepper and sear in the center of the pan for 3 minutes per side to develop a crust.
  4. Deglaze the pan by adding the balsamic vinegar and dry sherry, scraping the bottom to release the browned bits. Pour in the beef bone broth and add fresh thyme.
  5. Nestle the chicken under the onion mixture. Place baguette slices on top, then sprinkle evenly with Gruyère and Parmesan cheeses.
  6. Transfer the skillet to a preheated oven at 400°F (200°C) and bake for 15 minutes or until the cheese is bubbly and golden and the chicken reaches an internal temperature of 165°F.