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–+ servings

Ultimate French Onion Chicken Casserole

Caramelized onions, tender chicken, and creamy Gruyère make this French onion chicken casserole pure comfort.
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Prep Time 15 minutes
Cook Time 35 minutes
Total Time 50 minutes
Servings: 1
Course: Chicken, Main Course
Cuisine: French
Calories: 540
Ingredients Method Nutrition Notes

Ingredients
  

Main Components
  • 2 lb boneless, skinless chicken breasts cut into bite-size pieces
  • 3 large yellow onions thinly sliced
  • 4 cloves garlic minced
  • 2 cups low-sodium chicken broth preferably unsalted or homemade
  • 1 cup heavy cream or heavy whipping cream
  • 1 teaspoon dried thyme or 1 tbsp fresh thyme leaves
  • 1 cup shredded Gruyère cheese about 4 oz / 115 g
  • 2 tablespoons extra-virgin olive oil California-grown, if available
  • 1 cup fresh breadcrumbs make them from sourdough for extra flavor
  • 2 tablespoons unsalted butter melted
Seasoning
  • to taste kosher salt
  • to taste freshly ground black pepper

Method
 

  1. Preheat the oven to 375°F (190°C) and lightly grease a 9x13-inch baking dish.
  1. Warm the olive oil in a large, heavy skillet over medium heat. Add the sliced onions and cook, stirring occasionally, until deeply golden and caramelized, 20 to 25 minutes.
  1. Stir in the minced garlic and cook for 1 minute until fragrant.
  1. Cut the chicken breasts into 1-inch chunks, then add them to the skillet. Season generously with salt, pepper, and thyme. Cook until the chicken is just beginning to brown on the edges, 5 to 7 minutes.
  1. Pour in the chicken broth, scraping up any browned bits from the bottom. Let the mixture simmer for 5 minutes.
  1. Remove the skillet from the heat and stir in the heavy cream until well combined.
  1. Transfer the mixture into the prepared baking dish and scatter the shredded Gruyère over the top.
  1. In a small bowl, toss the fresh breadcrumbs with the melted butter. Sprinkle this crumb mixture over the cheese.
  1. Bake for 30 to 35 minutes, until the casserole is bubbling around the edges and the cheese is melted and golden on top.
  1. Let the casserole rest for 10 minutes before serving to allow the sauce to set.

Nutrition

Calories: 540kcalCarbohydrates: 17gProtein: 42gFat: 33gSaturated Fat: 17gCholesterol: 140mgSodium: 450mgFiber: 2gSugar: 5g

Notes

Swap the heavy cream for half-and-half or whole milk for a lighter sauce.
Gruyère can be replaced with Swiss or sharp Provolone if needed.
Assemble the casserole through step 7 a day ahead; refrigerate and add the breadcrumb topping before baking.
Leftovers keep in an airtight container in the refrigerator for up to 3 days.
Use a large skillet so the onions caramelize evenly without crowding.
Serve over egg noodles, mashed potatoes, or with extra crusty bread.

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