Easy French Onion Chicken Casserole

French Onion Chicken Casserole that's creamy, cheesy, and full of flavor is made with tender chicken breast, rich cream sauce, and a crispy fried onion topping. This recipe is like a French Onion Dip Chicken Casserole, but baked with no pasta, no noodles, and no rice, making it low-carb and keto-friendly. You'll get one of the best dinner recipes that's easy to make, healthy, and packed with creamy shredded chicken the whole family will enjoy. Pin this French Onion Chicken Casserole so you'll always have a quick weeknight dinner idea ready for cozy evenings!

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Why is this the best French onion chicken casserole recipe

It's a simple and easy recipe. This tasty casserole is as easy as dumping a few ingredients in a baking dish together; it doesn't get any easier than that! Everyone loves a one-pan assembly! There's minimal clean-up, and prep time is quick, especially if you use store-bought rotisserie chicken!

The ingredients for this easy recipe are very common and very inexpensive. You probably have most of the simple ingredients already in your pantry, and the remaining couple are available in every grocery store I've ever visited.

French onion chicken casserole is versatile. You can use a mix of any two cheeses you'd like. There are several options for purchasing or making the fried onions; both would be delicious! If you want to replace the French onion dip with another flavor of dip, you can. You could make Ranch dip chicken casserole or veggie dip chicken casserole or whatever flavor you can find (or make!). You can be creative with this recipe.

This quick and easy French onion chicken casserole is the best comfort food. The simple ingredients pack a big punch in terms of flavor and texture. The creamy mix of cheeses, the flavorful French onion dip, the crispy fried onions on top, and the flavorful blend of sour cream, Worcestershire sauce, garlic powder, thyme, and Dijon mustard make it the best French onion chicken casserole you've ever eaten!

This recipe is easy to serve. It doesn't get easier than a dump-and-go casserole that you can make ahead, making it a perfect weeknight dish for a busy mom or dad.

This recipe is a family favorite. Kids especially love this comforting meal. The taste of the creamy, cheesy sauce, tender shredded chicken, and the crispy topping? Chef's kiss.

What you'll need to make French onion dip casserole

Equipment

Chicken shredder - This is the coolest gadget. You put a warm chicken breast in it, twist it a few times, and you have perfectly shredded chicken in under a minute. Sometimes, you have to readjust the larger pieces and twist a second time (especially if you got the chicken nicely browned and a little crispy on the outside), but I will never shred chicken with forks again!

9x9 casserole dish - This is obviously to bake the casserole. If you want to double the recipe, you can make it in a 9x13 pan.

Ingredients

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See the printable recipe card at the bottom of the page for all measurements and nutritional information.

• Shredded chicken - This can be rotisserie chicken, leftover roast chicken, or a chicken breast that you've just cooked. It'll take about 1.5 pounds of boneless skinless chicken to make enough shredded chicken. You can use boneless skinless chicken breasts or chicken thighs.
• French Onion dip - This is the star of the show! As I mentioned above, you can really use any dip you want including ranch dip or vegetable dip. But French onion dip is by far my favorite.
• Sour cream - This adds creaminess to the dish and tones down the dip flavor just a smidge.
• Dijon mustard - This gives the casserole a little tanginess. Any mustard will work, but Dijon has an almost sweet flavor that really complements the French onion dip.
• Worcestershire sauce - This is a slight umami flavor that adds a little saltiness and a rich undertone you'll miss if you leave it out.
• Garlic powder - You can press a couple of garlic cloves if you prefer fresh garlic.
• Dried thyme - This gives a subtle flavor. You could substitute with almost any dried herb from dill to oregano. Obviously, the herb you choose will change the flavor of the casserole.
• Shredded Swiss cheese or Gruyère - This is a versatile dish. Use whatever cheese you want. I chose Swiss because it's a little tangy which goes well with the Dijon mustard and French onion dip, but sharp cheddar cheese is always a safe bet as are most of the shredded cheese blends you can buy in the grocery store. Purists will tell you that you should shred your own cheese, but I never have and never will. The store-bought shredded cheese is fine.
• Shredded mozzarella and provolone - I found a mix of mozzarella and provolone at my grocery store, and that's what I used. If you can find shredded provolone, just provolone, that would be ideal, but I couldn't, and as I just said, I don't grate my own cheese. You could also use all mozzarella if you wanted to. Or whatever cheese. It's your casserole.
• French-fried onions - These are essential and make the casserole so good. I wouldn't ever make it without fried onions. However, if you don't want to use them, you could use crushed up Ritz crackers or toasted breadcrumbs instead. Or even cornflakes if you want a gluten-free casserole.
• Salt & pepper - I don't think these are necessary because the French onion dip is already seasoned, and also because cheese is salty. If you normally prefer to add salt and pepper, taste the casserole filling before adding it to the pan and adjust the seasonings as you need to.

How to make easy French onion chicken casserole

1. Preheat oven to 375°F. There is no need to grease the casserole dish because this recipe contains plenty of fat and won't stick.
2. In a large bowl, combine French onion dip, sour cream, Dijon mustard, Worcestershire sauce, garlic powder, and thyme. Mix until smooth.
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3. Stir in the shredded chicken mixture and half of the cheese. Add a splash of milk, cream, or chicken broth if the mixture feels too thick. Pour into the baking dish and smooth out the top.
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4. Sprinkle the remaining cheese evenly on top.
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5. Sprinkle the French-fried onions over the cheese.
6. Bake uncovered for 30-35 minutes until hot and bubbly with a golden topping. Check around 20 minutes and ensure the onions aren't getting too brown. If they are deeply brown, cover the casserole with aluminum foil for the rest of the time.
7. Cool for at least 5 minutes before serving.
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Substitutions & variations

Use any dip, store-bought or your favorite homemade version for this creamy chicken casserole. French onion dip is my preference, but you could use ranch dip, vegetable dip, jalapeño dip, whatever you want. I would stick to a sour cream or mayo-based dip.

To make an easy homemade French onion dip, combine a packet of onion soup mix with 2 cups of sour cream. Blend well and let sit for an hour or so before adding to your casserole.

I would like to add sautéed mushrooms and/or caramelized onions for an extra flavor boost. If my kids didn't hate them, I would add both. You could also add chopped green peppers, zucchini, broccoli, grated carrots, or cauliflower. Whatever vegetables you use, cook them in some butter in a skillet before adding to the casserole. Vegetables typically don't cook all the way when baked in a casserole like this. (To caramelize onions, you start with a sweet Vidalia or yellow onion. Cut them into slices or rings. Melt butter in a large skillet over medium-high heat. When the butter is hot, turn the heat to medium-low and add the onions. Stir occasionally until the onions are soft. Stir in a teaspoon or two of brown sugar over the onions and continue to cook them until they are deeply brown. This process will take 30 to 45 minutes but it is worth it because caramelized onions have next level flavor that would make this casserole amazing.)

You can add carbs if you want them. You could add 2 cups of pre-cooked brown or white rice, cauliflower rice, egg noodles, or the pasta shape of your choice with the chicken. You may want to add a cup or so of broth, milk, or cream to the mixture to account for the moisture that the carbs will soak up. (Make sure the rice or pasta is COOKED before adding it! It will not cook in the casserole. You need to boil it first.)

Make it a one-pan bake by skipping the bowl and mixing your french onion chicken bake directly in the casserole dish.

For a smokier taste, mix in a little smoked paprika or use smoked cheese.

For a slightly different flavor, you could replace the sour cream with cream of chicken soup, cream of mushroom soup, or cream of celery soup. This would make the casserole taste less onion-y.

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Try topping with crumbled Ritz crackers, buttery breadcrumbs, crushed up potato chips, or corn flakes if you don't have fried onions.

For a touch of sweetness, stir in a spoonful of caramelized onion jam.

Make individual portions in ramekins for serving at gatherings.

Garnish with fresh thyme or parsley for a pop of color when serving.

Make ahead french onion casserole

You can make French onion chicken bake ahead. Simply prepare the casserole as directed, but stop before adding the crispy onions. Cover the dish with plastic wrap and store in the fridge for up to 3 days. Remove, sprinkle with fried onions, and bake as directed. Baking from chilled will take 10-15 minutes longer.

Storing leftovers

Refrigerate leftovers in an airtight container in the refrigerator for up to 4 days. Reheat in oven or microwave until warmed through.

You can also freeze this casserole. Make sure you place it into an airtight container or freezer bag. When you want to reheat: thaw in the fridge overnight. Bake at 350ºF until warmed through (about 20-25 minutes.)

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Check out more deliciously cheesy casserole recipes:

• Beef Enchilada Casserole
• Buffalo Chicken Pasta Casserole
• Cheesy Green Bean Casserole
• Cauliflower Mac & Cheese
• Cheesy Chicken Hashbrown Casserole
• Mexican Layered Chicken Casserole
• Cheesy Shrimp Casserole with Velveeta
• Broccoli, Cheese, and Rice Casserole

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