French Onion Chicken Orzo Casserole is a cozy one-dish meal that blends tender chicken, flavorful caramelized onions, and cheesy orzo pasta. The rich onion flavor walks hand in hand with gooey melted cheese, making this casserole a comforting dinner choice any night of the week.
I love how the caramelized onions give this dish a deep, slightly sweet taste that feels fancy but comes together so easily. Cooking the onions slowly until golden is my little secret for bringing out that amazing flavor, and the orzo soaks it all up beautifully. It’s always a crowd-pleaser in my house because it’s hearty without being heavy.
One of my favorite things about this casserole is how it’s perfect for a simple weeknight dinner but still feels special enough to share with guests. I like to serve it with a green salad on the side to add a fresh crunch. Leftovers reheat nicely too, so it’s great for planning ahead and enjoying again the next day.
Key Ingredients & Substitutions
Yellow Onions: These are the heart of the dish. Their natural sugars caramelize beautifully for that deep, rich flavor. If needed, sweet onions or even shallots can work, but they’ll be milder.
Chicken: I like using cooked shredded chicken breasts or thighs. Thighs stay juicier but breasts are leaner. Rotisserie chicken is a great shortcut here too.
Orzo: This small pasta cooks quickly and soaks in flavors well. If you don’t have orzo, tiny pasta like acini di pepe or even small rice can be used.
Gruyère Cheese: It melts perfectly and adds a nutty note. Swiss cheese is a good substitute. Mozzarella can be added for extra stretchiness but it’s less flavorful alone.
Sour Cream or Greek Yogurt: This adds creaminess and a slight tang. Greek yogurt is a healthier swap if you want fewer calories. Just avoid flavored varieties.
How Do You Get Perfectly Caramelized Onions for That Deep Flavor?
Caramelizing onions takes time but is key to the casserole’s amazing taste. Here’s how I do it:
- Slice onions thinly for even cooking.
- Cook them on medium-low heat with butter and a pinch of salt to draw out moisture and sweetness.
- Stir every few minutes. This slow cooking (about 25-30 minutes) lets natural sugars break down and turn golden brown.
- Add garlic and thyme near the end to keep flavors fresh.
- Deglaze with a splash of white wine if you like, letting it cook off to concentrate flavor.
Patience here pays off with rich, sweet onions that make the whole casserole shine.
Equipment You’ll Need
- Large skillet or frying pan – I prefer this for caramelizing onions evenly without crowding.
- Mixing bowl – for combining cooked chicken, onions, and pasta easily.
- 9×13-inch baking dish – the perfect size for the casserole to cook evenly and be easy to serve.
- Whisk or spoon – to stir ingredients and combine flavors smoothly.
- Oven – preheated to 375°F (190°C) for baking the casserole to bubbly perfection.
Flavor Variations & Add-Ins
- Cheese swap: Use Swiss or mozzarella if Gruyère isn’t available—each melts well and adds flavor.
- Veggie boost: Mix in sautéed mushrooms, spinach, or bell peppers for added color and nutrients.
- Spice it up: Add a pinch of paprika or cayenne pepper to give a subtle kick.
- Extra herbs: Fresh thyme, rosemary, or parsley can be added for more aroma and freshness.
French Onion Chicken Orzo Casserole
Ingredients You’ll Need:
- 1 lb (450 g) boneless, skinless chicken breasts or thighs, cooked and shredded
- 4 large yellow onions, thinly sliced
- 3 tbsp unsalted butter
- 2 cloves garlic, minced
- 1 tsp fresh thyme leaves (or 1/2 tsp dried thyme)
- 1/4 cup dry white wine (optional)
- 1 cup orzo pasta (uncooked)
- 3 cups chicken broth
- 1 cup sour cream or Greek yogurt
- 1 cup shredded Gruyère cheese, divided (or Swiss cheese)
- 1/2 cup grated Parmesan cheese
- Salt and freshly ground black pepper, to taste
- Fresh parsley, chopped (for garnish)
Time Needed
Prep time: About 40 minutes (mostly for caramelizing onions and mixing ingredients).
Bake time: 25-30 minutes.
Total time: Approximately 1 hour.
Step-by-Step Instructions:
1. Caramelize the Onions
Start by melting butter in a large skillet over medium heat. Add the thinly sliced onions and a pinch of salt. Cook them slowly, stirring occasionally, for about 25-30 minutes until they turn a rich golden brown and smell sweet. In the last two minutes, stir in the minced garlic and thyme. If you want, pour in white wine and let it simmer until most of the liquid evaporates. Take the pan off the heat when done.
2. Preheat Oven
Set your oven to 375°F (190°C) to warm up while you prepare the rest of the dish.
3. Mix Chicken, Orzo, and More
In a large bowl, combine the cooked shredded chicken, caramelized onions, uncooked orzo pasta, chicken broth, sour cream, half of the shredded Gruyère cheese, and the Parmesan cheese. Stir everything well, then season with salt and freshly ground black pepper to your liking.
4. Assemble and Bake the Casserole
Grease a casserole dish and pour in the mixture, spreading it out evenly. Sprinkle the remaining Gruyère cheese on top. Place it uncovered in the oven and bake for 25-30 minutes, or until the orzo is tender and the top is bubbly and golden.
5. Garnish and Serve
Once baked, let the casserole cool slightly for a few minutes. Sprinkle with freshly chopped parsley before serving. Enjoy your warm, cheesy, and flavorful French Onion Chicken Orzo Casserole!
Can I Use Frozen Chicken for This Casserole?
Yes! Just make sure to fully thaw the chicken before cooking and shredding it. Thaw in the fridge overnight or use the cold water method for quicker thawing.
Can I Substitute the Gruyère Cheese?
Absolutely! Swiss cheese is a great substitute with a similar taste and melt. You can also mix in mozzarella for extra gooeyness, though it has a milder flavor.
How Do I Store Leftovers?
Store leftovers in an airtight container in the fridge for up to 3 days. Reheat gently in the microwave or oven until warmed through, adding a splash of chicken broth if it seems dry.
Can I Make This Dish Ahead of Time?
Yes, you can prepare the casserole up to the baking step and refrigerate it for up to 24 hours before baking. Just bring it to room temperature before putting it in the oven for best results.