Ingredients:

  • 4 (6 oz / 170g) boneless, skin-on chicken thighs
  • 1 tbsp (15ml) olive oil
  • 1 tsp (6g) kosher salt
  • ½ tsp (3g) cracked black pepper
  • 3 large (450g) yellow onions, thinly sliced
  • 3 tbsp (42g) unsalted butter
  • ½ tsp (3g) granulated sugar
  • ¼ tsp (1.5g) salt
  • ½ cup (120ml) dry white wine
  • 1 cup (240ml) low-sodium beef broth
  • 1 tsp (5g) fresh thyme leaves
  • 1 tbsp (15g) all-purpose flour
  • 1 ½ cups (170g) grated Gruyère cheese
  • 1 tbsp (15g) fresh parsley, chopped

Instructions:

  1. Pat the chicken thighs completely dry with paper towels. Season both sides generously with salt and pepper.
  2. Heat olive oil in an oven-safe skillet over medium-high heat until shimmering. Place chicken skin-side down and cook for 5–7 minutes without moving until the skin is golden brown. Flip and cook for another 3 minutes, then remove chicken to a plate.
  3. Reduce heat to medium. Add butter to the remaining chicken fat in the skillet. Stir in sliced onions and a pinch of salt.
  4. Cook onions, stirring occasionally, for 12–15 minutes. Stir in the sugar halfway through the process to encourage deep browning.
  5. Pour in the white wine or beef broth. Use a wooden spoon to scrape up the brown fond (caramelized bits) from the bottom of the pan.
  6. Stir in the remaining beef broth, fresh thyme, and all-purpose flour. Return the chicken thighs to the skillet, nesting them into the onions.
  7. Top the chicken and onions with grated Gruyère cheese. Transfer the skillet to the oven or use a broiler until the cheese is bubbling and golden, and the chicken is fully cooked.
  8. Garnish with chopped fresh parsley before serving.