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French Onion Chicken

A comforting and elegant weeknight dinner featuring tender chicken, caramelized onions, and gooey Gruyere cheese, reminiscent of classic French onion soup.
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Prep Time 15 minutes
Cook Time 1 hour 5 minutes
Total Time 1 hour 20 minutes
Servings: 4 servings
Course: Dinner, Main Course
Cuisine: Comfort Food, French
Calories: 450
Ingredients Method Notes

Ingredients
  

For the Chicken
  • 4 pieces boneless, skinless chicken breasts (about 1.5 to 2 pounds), patted dry
  • 1 teaspoon kosher salt
  • 1/2 teaspoon black pepper
  • 1 tablespoon olive oil
  • 1 tablespoon unsalted butter
For the Caramelized Onions and Sauce
  • 3 large yellow onions, thinly sliced (about 6 cups) Use firm, fresh onions for best caramelization.
  • 2 tablespoons unsalted butter
  • 1 tablespoon olive oil
  • 1 teaspoon sugar (helps with caramelization, optional)
  • 2 cloves garlic, minced
  • 1/2 cup dry white wine or dry sherry (substitute: extra broth)
  • 1 1/2 cups beef broth or low-sodium beef stock (for deeper flavor) Gives classic French onion depth.
  • 1 teaspoon fresh thyme leaves or 1/2 teaspoon dried thyme
  • 1 tablespoon balsamic vinegar (brightens the sauce)
  • 1 tablespoon cornstarch mixed with 2 tablespoons cold water (optional, for thickening)
For Finishing
  • 1 cup grated Gruyere or Swiss cheese Gruyere gives a nutty melt; for a milder option, use Swiss or fontina.
  • 2 tablespoons chopped fresh parsley for garnish
  • Salt and pepper to taste

Method
 

Prep the onions and chicken
  1. Slice the onions thinly and pat the chicken dry. Season the chicken with salt and pepper.
Caramelize the onions
  1. In a large skillet over medium heat, add 2 tablespoons butter and 1 tablespoon olive oil.
  2. Add the sliced onions and 1 teaspoon sugar if using. Cook gently, stirring every few minutes, until the onions are a deep golden brown and very soft, about 30 to 40 minutes.
  3. If the pan looks dry, add a splash of water to deglaze and prevent burning. Add the minced garlic in the last 2 minutes of cooking.
Brown the chicken
  1. While onions caramelize, heat 1 tablespoon olive oil and 1 tablespoon butter in a second large skillet over medium-high heat.
  2. Add chicken and brown 2 to 3 minutes per side, until golden. The chicken will not be fully cooked; remove and set aside.
Build the sauce
  1. To the caramelized onions, add the white wine to deglaze the pan, scraping up browned bits. Let the wine reduce by half, about 2 to 3 minutes.
  2. Stir in the beef broth, thyme, and balsamic vinegar. Bring to a simmer and allow flavors to meld, 3 to 5 minutes.
  3. If you prefer a thicker sauce, stir in the cornstarch slurry and simmer until slightly thickened.
Combine and finish in the oven
  1. Preheat oven to 375°F (190°C).
  2. Nestle browned chicken into the onion sauce in an ovenproof skillet or transfer everything to a baking dish. Spoon sauce over the chicken.
  3. Sprinkle 1 cup grated Gruyere evenly over the chicken and onions.
  4. Bake, uncovered, for 20 to 25 minutes, until the chicken reaches an internal temperature of 165°F (74°C) and the cheese is bubbly and golden.
Rest and serve
  1. Let the dish rest for 5 minutes. Garnish with chopped parsley and serve.

Notes

Leftovers keep well in the fridge for 3 to 4 days. Reheat gently in a skillet over low heat or in a 325°F oven covered for 10 to 15 minutes. To freeze: store cooled portions in airtight containers up to 2 months. Thaw overnight in the fridge before reheating.