Name: French Onion Chicken Casserole
Prep time: 10 min
Cook time: 40 min
Total time: 50 min
Ingredients: 4 cups cooked chopped chicken (leftover, rotisserie or poached chicken work well); 1 cup shredded cheddar cheese (sharp or mild, depending on preference); 1 cup refrigerated sour cream French Onion Dip; 1 can (10.5-oz) unsalted cream of chicken soup; 1 can (2.8-oz) French fried onions (reserve a few for garnish, if desired)

I still remember the first time I baked this French Onion Chicken Casserole — warm, savory, and impossibly simple. It’s essentially shredded chicken folded into a creamy French onion dip base, topped with crispy fried onions and baked until bubbling. Families love it because it’s fast, forgiving, and gives you that caramelized onion flavor without the long slow-cooking. If you like shortcuts that taste homemade, this is a weeknight hero (and yes, it pairs nicely with classic French onion techniques if you want to go all-in on the onion flavor: classic French onion soup techniques).

Why you’ll love this dish

This casserole hits a sweet spot: it’s quick to assemble, uses pantry staples, and serves a crowd without standing over the stove. It’s perfect when you have leftover roast chicken or rotisserie on hand and need something warm and comforting for dinner or a potluck dish that travels well. The use of refrigerated French onion dip gives the casserole an instant flavor boost — a shortcut to deep onioniness that many kids and adults approve of.

“Crispy onions on top, creamy inside — tastes like you spent hours fussing when you really spent 10 minutes prepping.” — a regular at my Sunday suppers

If you want a slow-cooker version later, there’s a great crockpot variation you can reference for different timing and texture: crock-pot variation.

Step-by-step overview

Before you gather ingredients, here’s the process at a glance so you know what to expect:

Preheat the oven to 350°F and prepare a 9×9-inch pan.
Stir cooked chopped chicken with cheddar, French onion dip, and cream of chicken soup until evenly combined.
Spread the mixture into the pan, top with French fried onions, and bake uncovered.
Bake 30–40 minutes until heated through and top is golden-crisp.

This recipe is largely assembly, then bake — minimal hands-on time, about 10 minutes prep.

What you’ll need

4 cups cooked chopped chicken (leftover, rotisserie or poached chicken work well)
1 cup shredded cheddar cheese (sharp or mild, depending on preference)
1 cup refrigerated sour cream French Onion Dip
1 (10.5-oz) can unsalted cream of chicken soup
1 (2.8-oz) can French fried onions (reserve a few for garnish, if desired)

Substitution notes:

Use Greek yogurt-based French onion dip for a tangier, higher-protein swap.
Swap cheddar for Swiss or Gruyère for a nuttier profile.
For a gluten-free option, use gluten-free fried onions or a crunchy gluten-free topping.

Directions to follow

Preheat oven to 350°F. Lightly spray a 9×9-inch baking dish with cooking spray.
In a large bowl, combine the chopped cooked chicken, shredded cheddar, French onion dip, and the can of cream of chicken soup. Mix until evenly combined and creamy.
Spread the chicken mixture into the prepared baking dish in an even layer.
Sprinkle the can of French fried onions evenly over the top. Save a small handful to add after baking if you want extra crunch.
Bake uncovered for 30 to 40 minutes, until the casserole is hot and bubbly and the onions on top are golden. If the top browns too quickly, loosely tent with foil.
Let rest 5 minutes before serving to allow the casserole to settle.

Cooking tip: because the chicken is already cooked, you’re heating to meld flavors and crisp the topping rather than cooking raw meat. Aim for an internal serving temperature of at least 165°F when reheating leftovers.

Best ways to enjoy it

This casserole pairs well with crisp, bright sides to cut through the richness:

A simple green salad with a lemon vinaigrette.
Steamed green beans or roasted Brussels sprouts.
Buttery mashed potatoes or egg noodles for a full comfort-food plate.
Serve with warm crusty bread to scoop the creamy interior.

For a fun combo at a casual dinner, serve it alongside a small plate of French onion meatballs (a complementary flavor profile): serve alongside French onion meatballs.

Storage and reheating tips

Refrigerator: Store leftovers in an airtight container for 3–4 days. Reheat in the oven at 350°F covered with foil until warmed through (about 15–20 minutes), or microwave individual portions until hot.
Freezer: Freeze cooled casserole in a freezer-safe container for up to 2 months. Thaw overnight in the refrigerator before reheating.
Food safety: When reheating, bring the casserole to 165°F to ensure food safety. Avoid leaving the dish at room temperature for more than 2 hours.

Helpful cooking tips

Use bite-sized chicken pieces so every bite has a good balance of chicken and creamy sauce.
If your French onion dip is on the runny side, drain excess moisture from shredded chicken to prevent a soupy casserole.
For extra flavor, fold in 1/4 cup caramelized onions or a teaspoon of Worcestershire sauce.
If you prefer a crunchier top, add half the fried onions before baking and sprinkle the rest on for the final 5 minutes of baking.
To make it lower in sodium, choose reduced-sodium cream of chicken soup and unsalted fried onions, then season to taste.

For more slow-cooker inspiration and techniques that adapt well to casseroles, this crockpot French onion chicken guide is handy: slow-cooker tips and adaptation.

Creative twists

Vegetarian swap: Replace chicken with cooked chopped cauliflower or a mix of mushrooms and use a vegetable cream soup.
Tex-Mex twist: Stir in 1 cup black beans and swap cheddar for pepper jack. Top with crushed tortilla chips instead of fried onions.
Low-carb option: Serve over riced cauliflower or zucchini noodles and skip starchy sides.
Gourmet upgrade: Fold in caramelized onions, use Gruyère, and top with panko mixed with melted butter for a bistro-style version.

Your questions answered

Q: Can I use raw chicken in this recipe?
A: No — this recipe assumes cooked chicken. If you start with raw chicken, poach or roast it first until it reaches 165°F, then chop and proceed. If you bake raw chicken in the casserole, you’ll need to increase the overall bake time and ensure the internal temperature reaches 165°F.

Q: How long does prep actually take?
A: Active prep time is about 8–12 minutes if your chicken is already cooked. The bake time is 30–40 minutes.

Q: Can I double the recipe?
A: Yes. Double ingredients and bake in a 9×13-inch pan. Baking time may increase slightly; check for bubbling edges and a hot center.

Q: Are there dairy-free options?
A: Replace the French onion dip with a dairy-free onion dip and use dairy-free cream soup and cheese alternatives. Texture and flavor will change, but the concept remains the same.

Q: Why do you recommend a 9×9 pan?
A: A 9×9 gives the right thickness for even heating and a crunchy top. Larger pans spread the mixture thinner and may bake faster.

Conclusion

If you want to compare similar takes or see alternative prep notes, these two tested recipes are excellent references: French Onion Chicken Casserole – Plain Chicken and French Onion Chicken Casserole {Only 10 Minutes to Prep!} | Lil’ Luna. Both offer slight variations that can inspire how you season, top, or serve this easy, crowd-pleasing casserole.