Ingredients:

  • 3 large (450g) yellow onions, thinly sliced
  • 3 tbsp (42g) unsalted butter
  • 1 tbsp (15ml) olive oil
  • 1 tbsp (15g) brown sugar
  • 1 tsp (5g) fresh thyme leaves
  • 1/2 tsp (3g) salt
  • 2 lbs (900g) boneless skinless chicken thighs
  • 2 cups (480ml) beef stock (low sodium)
  • 1 tbsp (15ml) Worcestershire sauce
  • 1 tbsp (15ml) balsamic vinegar
  • 1/2 cup (120ml) heavy cream
  • 2 tbsp (16g) cornstarch
  • 1 1/2 cups (170g) shredded Gruyère cheese
  • 1/2 cup (56g) shredded mozzarella cheese
  • 1 French baguette, sliced into 1/2 inch (1.25cm) rounds

Instructions:

  1. Heat butter and olive oil over medium-high heat in an oven-safe skillet. Add sliced onions and sauté until they begin to soften.
  2. Stir in brown sugar and thyme, then reduce heat to medium. Cook, stirring occasionally, until onions reach a deep mahogany color and smell nutty (approximately 12–15 minutes). Remove onions from the pan and set aside.
  3. Increase heat to medium-high. Pat chicken thighs dry and season with salt and pepper. Sear chicken for 3–5 minutes per side until a golden-brown crust forms. Remove chicken from the pan.
  4. In a small bowl, whisk cornstarch into the cold beef stock until dissolved. Pour the mixture into the skillet, scraping up the browned bits from the bottom.
  5. Stir in Worcestershire sauce and balsamic vinegar. Simmer for 3 minutes until slightly thickened, then stir in the heavy cream.
  6. Stir the caramelized onions back into the sauce and nestle the seared chicken thighs into the mixture.
  7. Top each piece of chicken with baguette rounds and a blend of Gruyère and mozzarella cheese. Bake until cheese is bubbly and golden.