Ingredients:

  • 1.5 lbs chicken thighs, boneless and skinless
  • 1 tsp kosher salt
  • 1/2 tsp cracked black pepper
  • 2 tbsp extra virgin olive oil
  • 3 large yellow onions, thinly sliced (approx. 900g)
  • 3 tbsp unsalted butter
  • 2 cloves garlic, minced
  • 1 tbsp balsamic vinegar
  • 1/2 cup low sodium beef broth
  • 1 tsp fresh thyme leaves
  • 1.5 cups Gruyère cheese, shredded
  • 1/2 cup Parmesan cheese, freshly grated
  • 1/2 French baguette, sliced into 1-inch rounds

Instructions:

  1. Season the chicken with salt and pepper. Heat olive oil in a large oven-proof skillet over medium-high heat. Sear the chicken for 3–4 minutes per side until a deep golden crust forms. Remove chicken and set aside.
  2. In the same skillet, melt the butter. Add the sliced onions and a pinch of salt. Reduce heat to medium and cook, stirring occasionally, for 15–20 minutes until the onions are a rich mahogany brown. Stir in garlic and thyme during the last 2 minutes.
  3. Pour in the balsamic vinegar and beef broth. Scrape the bottom of the pan to release the fond. Return the chicken to the pan, nestling it into the onions. Top with baguette slices and cover with Gruyère and Parmesan cheeses.
  4. Transfer the skillet to the oven and bake at 400°F until the cheese is bubbling and golden and the chicken reaches an internal temperature of 165°F.