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French Onion Chicken Casserole

French Onion Chicken Casserole
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This French Onion Chicken Casserole is a weeknight lifesaver and family favorite, inspired by classic French onion soup. It captures the magic of deep savory broth, sweet caramelized onions, and gooey cheese crust in a single, hearty bake. Easy to make and packed with flavor, it's a comforting meal perfect for chilly evenings or family gatherings, quickly becoming a go-to in your meal rotation.

Ingredients

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2 lbs Boneless, skinless chicken breasts
3 large Yellow onions
4 tbsp Butter
2 tbsp Olive oil
4 cloves Garlic, minced
1/4 cup All-purpose flour
4 cups Beef broth
1/4 cup Dry sherry
1 tbsp Worcestershire sauce
1 tsp Fresh thyme leaves
1 tsp Salt
1/2 tsp Black pepper
8 oz Cream cheese, softened
1.5 cups Gruyère cheese, shredded
6–8 slices Provolone cheese, sliced
6–8 slices Crusty bread (e.g., baguette), sliced

Instructions

  1. Prep the Chicken: Preheat your oven to 375°F (190°C). Season the chicken breasts generously with salt and pepper. In a large oven-safe skillet or Dutch oven, heat 1 tbsp olive oil over medium-high heat. Sear the chicken for 3-4 minutes per side, until golden brown. It doesn't need to be cooked through at this stage. Remove the chicken from the skillet and set aside to cool slightly. Once cool enough to handle, shred or cube the chicke
  2. Caramelize the Onions: In the same skillet, add the remaining 1 tbsp olive oil and 4 tbsp butter over medium-low heat. Add the sliced onions. Cook them slowly, stirring occasionally, for 25-35 minutes, until they are deeply golden brown and sweet. Patience is key here; properly caramelized onions are the soul of this French Onion Chicken Casserole
  3. Build the Sauce Base: Stir in the minced garlic and cook for 1 minute until fragrant. Sprinkle the flour over the onions and cook for 2 minutes, stirring constantly, to create a roux
  4. Deglaze and Simmer: Gradually whisk in the beef broth, dry sherry (if using), Worcestershire sauce, and fresh thyme. Bring the mixture to a simmer, stirring until the sauce thickens slightly, about 5-7 minutes. Season with salt and pepper to taste
  5. Add Creaminess and Chicken: Reduce the heat to low. Add the softened cream cheese to the sauce, stirring until it's completely melted and smooth. Stir in 1 cup of the shredded Gruyère cheese until it's fully incorporated. Finally, fold in the shredded cooked chicken. Your French Onion Chicken Casserole filling is now ready!
  6. Assemble the Casserole: Transfer the chicken and onion mixture to a 9×13 inch baking dish. Arrange the sliced provolone cheese over the top of the chicken mixture
  7. Add Bread and Bake: Place the slices of crusty bread over the provolone cheese, covering the entire top of the casserole. Sprinkle the remaining 1/2 cup of shredded Gruyère cheese over the bread
  8. Bake to Perfection: Bake for 25-30 minutes, or until the casserole is bubbling, and the cheese topping is melted and golden brown. If the top isn't as golden as you'd like, you can briefly broil it for 1-2 minutes, watching carefully to prevent burning
  9. Rest and Serve: Let the French Onion Chicken Casserole rest for 5-10 minutes before serving. This allows the sauce to set slightly. This delicious French Onion Chicken Casserole is best served warm

Notes

Patience with Onions: Don't rush the caramelization process. Low and slow heat brings out the most incredible sweetness and depth of flavor.

Shredding Chicken: Cook chicken just until it reaches 165°F (74°C). After it cools, shred it using two forks or a stand mixer.

Seasoning Layers: Taste and adjust seasoning at each stage – after caramelizing onions, after making the sauce, and before adding the cheese.

Make Ahead: Assemble the casserole (without bread and final cheese) a day in advance, refrigerate. Add bread and cheese just before baking.

Storage: Leftovers keep for 3-4 days in the refrigerator in an airtight container. Freezes well for 2-3 months; thaw overnight before reheating.

Reheating: Reheat in oven at 350°F (175°C) until bubbling (20-30 mins for portions, 45-60 mins for whole casserole). Microwave individual servings for 2-3 mins.

Nutrition

Find it online: https://fabiloustaste.com/french-onion-chicken-casserole/