French Onion Chicken Casserole: Easy, Flavorful, and Budget-Friendly

This French Onion Chicken Casserole features tender chicken, rich French onion flavors, and a crispy topping, making it a perfect choice for a weeknight main dish. With less than ten simple ingredients, it’s also great for meal prep to enjoy lunches throughout the week!

Photo byThe Cookin' Chicks

In this house, we love a hearty chicken casserole. I’m constantly making Chicken Bacon Ranch Casserole, Ritzy Chicken Casserole, or spicing it up with Jalapeno Popper Chicken Casserole. Since they are always on rotation, I try and change up the flavors each time to add a unique twist like in this delicious French fried onion chicken casserole which has the same flavors of an onion ring!

With Crispy French Fried Onions

The French onion flavor comes from using a package of crispy French-fried onions on top. You may only see these during the holidays on top of green bean casserole, but they can be used for so much more! Essentially, they are thinly sliced onions that have been coated in flour and fried until golden brown and crunchy. Their crisp texture and rich, caramelized flavor add a crunchy and savory contrast to the creamy texture of a chicken casserole which really stands out.

Photo byThe Cookin' Chicks

Sneak In Veggies

I love adding green beans to this dish but feel free to swap in celery or any other veggie you have on hand. A sneaky trick to make sure my kids eat their veggies is by incorporating them into the casserole. They might try to pick them out at first, but soon realize they’re in every bite, making them too hard to pick out, resulting in clean plates and no complaints!

Just mix cooked chicken, green beans, cheddar cheese, sour cream, mayo, cream of chicken soup, and slivered almonds in a bowl. Spread it in a greased baking pan, bake at 400°F for 30 minutes, then top with French fried onions and bake for 5-8 minutes until golden brown. In under one hour, you can have this casserole ready to enjoy!

Why You’ll Love This Easy French Onion Chicken Casserole

• Dump and bake: The instructions are simple, mix everything together, top with crispy onions and cook until golden brown. Anyone can do it!
• Budget friendly: You can find everything needed for this casserole in your local grocery store, and they won’t cost a lot, making it a dinner that is easy on the wallet.
• Leftovers: A great way to meal prep using leftovers for lunch that taste even better the next day.
• Customizable: Use chicken you cooked yourself or a shredded rotisserie chicken to save time. Change up the flavors of the soup and add whatever veggies you have on hand. This casserole can be customized, so you can change it up each time.

Photo byThe Cookin' Chicks

Key Ingredient Notes & Substitutions

• Cooked Chicken – If you have leftover cooked chicken from another recipe, feel free to use it here. Otherwise, a rotisserie chicken makes it fast and easy. Use boneless, skinless chicken breasts exclusively or a mixture of chicken breast and chicken thigh meat.
• Vegetables – My kids will eat canned green beans, so you can usually find those tucked inside. Otherwise, try out other veggies like broccoli, carrots, mushrooms, zucchini, or greens like spinach.
• Cheddar Cheese – Shredded cheddar cheese helps the casserole set together and adds a creamy, sharp, and cheesy element that pairs well with the hearty ingredients.
• Sour Cream and Mayonnaise – This helps make up the base of the casserole and make it a true comfort food. You can lighten it up by using Greek yogurt or use reduced fat ingredients if you prefer.
• Cream of Chicken Soup – A can of condensed chicken soup helps to enhance the savory chicken flavor along with the creamy texture.
• Slivered Almonds – Adds a nutty crunch that goes well with the creamy nature of the dish.
• French’s Crispy Fried Onions – These savory and crunchy onion ring flavored bits enhance the dish with an overall onion taste and crispy topping that elevates the whole dinner.

Photo byThe Cookin' Chicks

How To Make French Onion Chicken Casserole

1. Prepare for baking: Preheat the oven to 400F. Spray a 9×13 inch baking dish with non-stick cooking spray and set aside.
2. Combine the ingredients: To a medium mixing bowl, add the cooked chicken, green beans, cheese, sour cream, mayo, cream of chicken soup, and slivered almonds. Toss to fully combine and evenly distribute the ingredients.
3. Initial bake: Pour the mixture into the prepared baking pan, spreading evenly. Bake for 30 minutes uncovered.
4. Add topping: Sprinkle the French-fried onions on top in an even layer. Bake for an additional 5-8 minutes or until the top is golden brown.
5. Cool and serve: Let the casserole cool for 5 minutes before serving. Enjoy!

Photo byThe Cookin' Chicks

Cooking Tips

• Mix the casserole ingredients thoroughly before adding to the baking pan to make sure each bite is flavored evenly.
• If you’re using fresh vegetables, blanch them first before adding them to the casserole, as they will not fully cook in the oven with the rest of the ingredients.
• Bake the casserole without the topping first to make sure the onions on top don’t burn. You could also place the onions on top, bake with a layer of foil on top, then remove in the last 5-8 minutes.
• For the best texture, let the baked casserole cool for 5 minutes. This allows the flavors to come together and helps the creamy texture thicken, making it easier to serve.

Customize It

• Swap out the cream of chicken soup for cream of mushroom or cream of celery.
• Add a teaspoon of Worcestershire sauce to the chicken mixture for an umami kick.
• Experiment with different types of cheese, such as Swiss, Mozzarella cheese, pepper jack, or Gruyère.
• Add cooked bacon pieces into the chicken mixture for a smoky flavor.
• For a spicy casserole, mix in diced jalapenos or add red pepper flakes to the chicken mixture.
• Use cooked turkey instead of chicken for an easy Thanksgiving leftovers meal.
• Stir in a handful of fresh herbs and spices like parsley, thyme, garlic powder, black pepper, a few cloves garlic, or rosemary to brighten up the flavor.
• Serve this casserole on a bed of cooked rice, quinoa, mashed potatoes, or pasta to bulk it up and make it even more hearty.

Storing & Freezing French Onion Chicken Casserole

• Storing: Store any leftovers in an airtight container in the refrigerator for up to 3-4 days.
• Freezing: Tightly wrap the cooled dish in aluminum foil or transfer it to a freezer-safe container. It can be stored in the freezer for up to 2-3 months. Let thaw overnight in the fridge before reheating.
• Reheating: To reheat, preheat your oven to 350°F. Place refrigerated casserole in the oven and bake until heated through, about 25-30 minutes. Microwave individual servings until warm.

Photo byThe Cookin' Chicks

FAQ’s

Can I make this chicken and French-fried onions casserole ahead of time?

Yes! This French Onion Casserole can be made ahead of time. Prepare the casserole without adding the French-fried onions until just before baking. Cover and refrigerate the assembled casserole for up to 24 hours, then sprinkle the onions on top and bake when ready to serve.

Can I make this recipe gluten-free?

You can easily make this recipe gluten-free by using gluten-free cream of chicken soup and making sure that the French-fried onions are also gluten-free. If you can’t find any, substitute gluten-free breadcrumbs or crushed gluten-free crackers for the topping, along with some dried minced onion for flavor.

Exact Ingredients

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• 3 cups chicken, cooked and shredded (or diced)
• 1 cup green beans (or veggie of choice)
• 1 cup cheddar cheese, shredded
• 1/2 cup sour cream
• 1/4 cup mayonnaise
• 1 can cream of chicken soup
• 1/4 cup almonds, slivered
• 6 oz. French fried onions