French Onion Chicken Casserole Recipe

When the air gets that crisp, cool bite, my cooking instincts immediately turn to cozy casseroles. There’s something so wonderfully comforting about a dish that bakes all in one pan, filling your kitchen with incredible aromas.

Today, we’re taking the deep, savory soul of a classic French onion soup and transforming it into a hearty, family-friendly main dish. It’s a clever twist that everyone at your table is going to adore.

This French onion chicken casserole is truly a celebration of flavor and texture. We’re talking rich, creamy, and packed with sweet caramelized onions right in the mix. The crowning glory?

A delightful, crunchy topping of those iconic French fried onions. My wife has declared this one of her favorite meals I make, and that’s a win in my book.

The smell alone, as those onions slowly caramelize, is absolutely worth the effort.

Why This Dish Is a Weeknight Hero

Beyond the incredible taste, this recipe is a practical dream for busy schedules. You can prep the entire casserole ahead of time and simply pop it in the oven when you’re ready.

It’s a fantastic option for having friends over, because the work is done beforehand. Or, let’s be real, it’s perfect for those chaotic nights shuttling kids to soccer practice.

You could even just caramelize the onions in advance if that helps streamline your dinner routine. The flexibility is a huge part of its charm.

Serve it over a bed of fluffy rice or some buttery noodles to soak up every bit of that delicious sauce. A simple green salad or steamed vegetable on the side cuts through the richness beautifully.

Ingredients Needed for the Recipe

Here’s what you’ll need to gather. Each component plays a specific role in building those deep, layered flavors we’re after.

• Sweet Onions (like Vidalia): These are the star, providing that essential sweet, deeply caramelized base flavor.
• Unsalted Butter: Used to slowly coax the sweetness out of the onions as they cook down.
• Boneless, Skinless Chicken Breasts: The hearty protein; try to find smaller ones for more even cooking.
• Dried Oregano & Garlic Powder: Simple seasonings that add an herbal and savory backbone to the chicken.
• Sour Cream (or Plain Greek Yogurt): Creates the luscious, tangy creaminess that binds the casserole together.
• Sharp Cheddar Cheese: Melts into the sauce, offering a bold, tangy punch that stands up to the onions.
• Cream of Chicken Soup: Acts as a convenient sauce base, adding savory depth and creaminess.
• Swiss, Gruyere, or Mozzarella Cheese (optional): An extra melty, browned cheese layer for that classic soup topping feel.
• French Fried Onions: Purely for that final, irresistible crunch and a boost of oniony flavor on top.

How to make French Onion Chicken Casserole?

The process is straightforward, but the payoff is huge. Just follow these simple steps.

Step 1 – Prep and Caramelize

Start by preheating your oven to 400°F and greasing a 9×13 inch baking dish. Now, for the most important part: the onions. Melt butter in a very large skillet over medium-high heat.

Add all of your thinly sliced sweet onions. They will seem like a mountain at first, but don’t worry. Cook for 5-7 minutes until they soften and begin to wilt down significantly.

Step 2 – Low and Slow

Reduce the heat to medium. This is where the magic happens. Let the onions cook slowly for about 15 more minutes, stirring occasionally.

You’re waiting for them to turn a lovely golden brown and become wonderfully soft and sweet. If the pan gets too dry, a splash of chicken broth will deglaze it and add more flavor.

Step 3 – Season and Assemble

While the onions work their magic, season your chicken breasts lightly with salt, pepper, oregano, and garlic powder. Place them in the bottom of your prepared dish.

In a medium bowl, mix the sour cream, shredded sharp cheddar, and the can of cream of chicken soup until it’s smooth and well combined.

Step 4 – Layer It Up

Spread your gorgeous caramelized onions evenly over the chicken breasts in the dish. Next, dollop the creamy cheese mixture over the onions.

Gently spread it into a somewhat even layer. If you’re using the optional extra cheese, now’s the time to sprinkle it generously over the top.

Step 5 – Bake and Finish

Bake the casserole, uncovered, for 40-45 minutes. You’ll know it’s done when the sauce is bubbly and the chicken reaches 165°F internally.

This is the crucial part: pull the dish out and quickly top it with the entire container of French fried onions. Return it to the oven for just 3-5 more minutes, watching closely so the topping gets crispy but doesn’t burn.

Smart Substitutions and Swaps

Don’t fret if you need to make a few changes. This recipe is quite adaptable. For the sour cream, plain Greek yogurt is a perfect one-to-one substitute, adding a protein boost. If you prefer, cream of mushroom soup can stand in for the cream of chicken for an earthier note.

The extra cheese on top is optional, but it really does add a special touch. Gruyere is the classic French onion soup choice, while mozzarella offers a fantastic, stretchy melt. And for a lighter twist, you could even use cauliflower rice as a base instead of regular rice when serving.

Tips

• Use the biggest skillet you have for the onions. They need space to caramelize properly, not steam.
• Resist the urge to crank the heat on the onions. True caramelization is a patient, medium-heat process.
• Always add the French fried onions at the very end. They go from golden to burnt in a flash if baked too long.
• Let the casserole rest for 5-10 minutes after baking. This allows the creamy sauce to thicken up slightly for perfect serving.

Mastering the Make-Ahead Method

This casserole’s make-ahead potential is a genuine game-changer. You can fully assemble it, cover the dish tightly with plastic wrap, and refrigerate it for 1-2 days before baking. Just pull it from the fridge as your oven preheats.

When baking a chilled casserole, simply add 5-10 minutes to the cooking time. You’re waiting for it to be heated all the way through and beautifully bubbly around the edges. Still, remember to add the crispy onion topping only for those final few minutes in the oven.

I truly hope you give this French onion chicken casserole a try. It wraps all the cozy, savory goodness of the beloved soup into a satisfying, feed-a-family meal. Enjoy every delicious, crunchy, creamy bite.

Happy cooking!

Print Recipe

French Onion Chicken Casserole Recipe

Author: Kelsey Perez Cooking Method: Baking Cuisine: American Courses: Dinner, Lunch

Difficulty: medium Prep Time 25 mins Cook Time 50 mins Rest Time 5 mins Total Time 1 hr 20 mins

Cooking Temp: 204  C Servings: 6 Estimated Cost: $ 18 Calories: 485

Best Season: Fall, Winter

Description

French onion chicken casserole is rich and creamy, with tons of caramelized onions mixed in and a crunchy French fried onion topping. The casserole can be prepped in advance and is great served over rice with a steamed vegetable for a delicious family dinner!

ingredients

Servings

For the onions:

• 2 tablespoons unsalted butter
• 3 large sweet onions (thinly sliced (e.g., Vidalia))
• Salt and black pepper (to taste)
• ¼ cup low sodium chicken broth (if needed for deglazing)

For the chicken:

• 4 (6 oz) boneless, skinless chicken breasts
• Salt and pepper (to taste)
• 1 teaspoon dried oregano
• 1 teaspoon garlic powder

For the casserole:

• 1 cup sour cream (or plain Greek yogurt)
• 1 cup shredded sharp cheddar cheese
• 1 (10.5 oz) can cream of chicken soup
• 1 cup shredded Swiss, Gruyere or mozzarella cheese (optional)
• 1 (6 oz) container French fried onions (added at the end)

Instructions

1. Preheat oven to 400°F (204°C). Grease a 9x13-inch or similar 3-quart baking dish with cooking spray and set aside.
2. Make the onions: Melt butter in a very large skillet over medium-high heat. Add the sliced onions and cook for 5–7 minutes, until softened. Season lightly with salt and pepper, reduce the heat to medium, and cook for 15 more minutes, stirring occasionally, until deeply caramelized. (If the pan dries out, add ¼ cup of chicken broth to deglaze.)
3. Season the chicken lightly with salt, pepper, oregano, and garlic powder. Place in the prepared baking dish.
4. In a medium bowl, mix together the sour cream, cheddar cheese, and cream of chicken soup until well combined.
5. Spoon the caramelized onions over the chicken in the baking dish. Dollop the creamy mixture over the onions and spread into an even layer. Top with the optional Swiss/Gruyere/mozzarella cheese.
6. Bake for 40–45 minutes, or until chicken reaches an internal temperature of 165°F. (Larger chicken breasts may require longer baking.)
7. Remove from oven and top with French fried onions. Return to oven for 3–5 more minutes, watching closely to prevent burning.
8. Let rest 5 minutes before serving. Garnish with fresh parsley if desired.

Nutrition Facts

Servings 6

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Amount Per Serving

Calories 485kcal

% Daily Value *

Total Fat 27g42%

Saturated Fat 14g70%

Cholesterol 135mg45%

Sodium 780mg33%

Potassium 560mg16%

Total Carbohydrate 22g8%

Dietary Fiber 2g8%

Sugars 6g

Protein 38g76%

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Calcium 25 mg

Iron 10 mg

* Percent Daily Values are based on a 2,000 calorie diet. Your daily value may be higher or lower depending on your calorie needs.

Note

• Make ahead: Assemble the casserole (without fried onions), cover, and refrigerate for 1–2 days. Bake at 400°F for 45–50 minutes, adding fried onions in the last 5 minutes.
• Serve it with: Rice, cauliflower rice, quinoa, angel hair pasta, or crusty bread—and a simple green salad or steamed vegetable on the side.
• Onion prep shortcut: Caramelize onions a day ahead to save time on baking day.

Keywords: French onion chicken casserole, creamy chicken casserole, caramelized onion casserole, baked chicken recipe, comfort food dinner