Ingredients

2 tablespoons olive oil

3 large yellow onions, thinly sliced

1/2 teaspoon granulated sugar

1/4 teaspoon salt

1/4 cup dry sherry or brandy

2 pounds boneless, skinless chicken thighs

1 teaspoon black pepper

1 teaspoon dried thyme

2 cups low-sodium chicken broth

1 tablespoon all-purpose flour

1 cup shredded Gruyere cheese

1/2 cup shredded Provolone cheese

2 tablespoons fresh thyme leaves

Instructions

Step 1: Heat the olive oil in a large oven-safe skillet or Dutch oven over medium-low heat. Add the sliced onions, granulated sugar, and salt. Cook slowly, stirring occasionally, for 30–40 minutes until the onions are deeply caramelized and golden brown.

Step 2: Increase the heat to medium and pour in the dry sherry or brandy. Scrape up any browned bits from the pan with a wooden spoon and cook for 2–3 minutes until most of the liquid evaporates. Remove the onions from the skillet and set aside.

Step 3: Pat the chicken thighs dry and season with black pepper and dried thyme. Add more olive oil to the skillet if needed. Sear the chicken over medium-high heat for 3–4 minutes per side until golden brown. Remove and set aside.

Step 4: Reduce heat to medium. Sprinkle the flour into the skillet and cook, stirring constantly, for 1 minute to make a roux. Gradually whisk in the chicken broth, scraping up any bits from the pan. Simmer for 3–5 minutes until the sauce thickens slightly.

Step 5: Return the caramelized onions to the skillet, then nestle the seared chicken thighs into the sauce and onions. Preheat the oven to 375°F (190°C). Sprinkle Gruyere and Provolone cheese evenly over the chicken and onions.

Step 6: Bake for 20–25 minutes until the chicken reaches an internal temperature of 165°F (74°C) and the cheese is bubbly and golden. For a golden crust, broil for 1–2 minutes, watching carefully to prevent burning.

Step 7: Remove from the oven and garnish with fresh thyme leaves and a grind of black pepper before serving.

Tips & Variations

Use chicken breasts if you prefer, but thighs remain juicier and more flavorful.

Substitute dry white wine for sherry or brandy if preferred.

Add a splash of balsamic vinegar to the onions while caramelizing for extra depth.

For a gluten-free option, use a gluten-free flour blend instead of all-purpose flour.

Serve with crusty bread or over mashed potatoes to soak up the delicious sauce.

FAQs

Can I use chicken breasts instead of thighs?

Yes, chicken breasts can be used, but they may be less moist than thighs. Adjust cooking time accordingly and avoid overcooking to keep them tender.

What can I substitute for dry sherry or brandy?

If you don’t have sherry or brandy, dry white wine or apple juice with a splash of vinegar can be used as substitutes. Each will slightly change the flavor but still enhance the dish nicely.