French Onion Chicken Casserole – The Big Man’s World ®

This French onion chicken casserole marries tender chicken with caramelized onions, crusty bread, and bubbling cheese all baked in one dish! It’s SO quick and easy to make.

Whether you’re craving French onion soup or you need a warm and hearty family dinner, this French onion chicken will hit the spot. It’s rich and savory and deceptively easy to make.

Not sure what this dish details? Well, it showcases well-seasoned and juicy chicken nestled in a creamy sauce with layers of caramelized onions, toasted baguette slices, and mounds of melted cheese. We love to make it for cozy family dinners, but it’s fab for serving guests, too!

Why this recipe works

• Quick and easy. Assembling this French onion chicken bake is a breeze! Turn to this recipe when craving comfort food that cooks up in minutes.
• All the textures! You get the tender chicken, crispy-soaked baguettes, and gooey cheese… what more could you want?
• No canned soup. Some French onion casserole recipes call for canned soup. On the other hand, Mine features upgraded flavors thanks to a chicken broth-based sauce made from scratch. 

Ingredients needed

You’ll love the simple ingredients in this casserole and the fact that you probably have most of them at home already. This is what you’ll need:

• Chicken breast. Boneless, skinless breasts are chopped into bite-sized pieces. If you don’t have chicken breasts at home, feel free to use boneless, skinless chicken thighs instead.
• Herbs and spices. Salt, pepper, dried thyme, and paprika are used to season the chicken and give every piece an indulgent, warm flavor.
• Butter. To prevent the chicken and onions from sticking in the pan.
• Onions. French onion soup is typically made with yellow onions, but almost any variety of onion will work. You can even use shallots if you have them on hand.
• Balsamic vinegar. This adds a sweet, acidic flavor that cuts through the other rich flavors. 
• Garlic. Freshly minced cloves.
• Chicken stock. Use a good-quality stock for the most comforting flavor.
• French baguette. To cover the casserole and add a buttery crunch to each bite, just like in traditional French onion soup. 
• Gruyere cheese. This is a classic cheese choice for French onion-inspired dishes. Provolone or Swiss cheese also works well. 

How to make a French onion chicken casserole

This recipe is easy to assemble, especially when you follow my time-saving tips below. Here’s an overview: 

Season the chicken: Cut the chicken into bite-size cubes, then season them with salt, pepper, thyme, and paprika. 

Brown the chicken: Cook the chicken in a hot buttered skillet until the pieces have browned. Transfer them to a baking dish. 

Caramelize the onions: Add more butter to the skillet, then add the onions. Cook until they’re golden and caramelized. Afterward, add in the balsamic and garlic, then cook until fragrant.  

Assemble and bake: Pour the onions over the chicken in the baking dish. Pour the chicken stock over top, then cover with the toasted baguette slices and grated cheese. Bake the casserole until the cheese is melted. 

Tips to make the best recipe 

• Slowly caramelize the onions. When done properly, this step can take between 30 minutes to 1 hour. Just be patient… You want to achieve that deep, caramelized flavor because it adds the timeless taste of French onion soup to this casserole. 
• Rest before serving. Let the casserole rest for a few minutes after baking to help the flavors meld together and firm up the texture.
• Time-saving tips. Speed up the recipe by browning the chicken, caramelizing the onions, and shredding the cheese 1 to 2 days ahead of time. You can also shred a store-bought rotisserie chicken to save even more time. 

Recipe and flavor variations

While I don’t recommend straying too far from the recipe, you can make a few small changes to customize it:

Add mushrooms. Sauté sliced mushrooms with the onions for extra flavor and texture.

Add bacon. Toss crispy bacon crumbles with the chicken and onions for an irresistible salty flavor and crunch. 

Vegetarian. Skip the chicken and make a vegetarian French onion casserole using plant-based chicken or roasted vegetables, like bell peppers, zucchini, onion, eggplant, or potatoes and carrots.

Low-carb. Cover your French onion chicken casserole with a low-carb substitute for the bread, like cauliflower rice or cauliflower mash.

Storage instructions

To store: Store the leftover casserole in an airtight container in the refrigerator for 3 to 4 days.

To freeze: After the unbaked casserole is assembled, cover the top with plastic wrap and aluminum foil and freeze for 2 to 3 months. Let it thaw overnight in the refrigerator and follow the baking instructions the next day. 

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Frequently asked questions