Name: French Onion Chicken Orzo Casserole
Prep time: 20 min
Cook time: 45 min
Total time: 1 h 5 min
Cuisine: American
Ingredients: 2 tablespoons butter; 1 tablespoon olive oil; 2 large yellow onions, thinly sliced; 2 teaspoons sugar; 2 teaspoons balsamic vinegar; 1 teaspoon salt; 1/2 teaspoon pepper; 3 cloves garlic, minced; 2 cups chopped cooked chicken (rotisserie or pre-cooked); 1 cup uncooked orzo pasta; 1/2 cup sour cream; 1/2 cup heavy cream; 1/2 cup chicken broth; 1 1/2 cups shredded mozzarella cheese, divided; 1/4 cup grated Parmesan cheese; Fresh thyme or parsley, for garnish (optional)

Why You’ll Love French Onion Chicken Orzo Casserole Recipe

Rich, layered flavour from those slow‑cooked caramelised onions and melted cheese.
Creamy, satisfying texture thanks to the orzo soaking up the sauce.
One‑dish convenience: everything comes together in one pan (and one bake).
Make‑ahead and freezer‑friendly: perfect for meal prep or planning ahead.
Elegant enough for guests, yet simple enough for a busy weeknight.

Ingredients

(Tip: You’ll find the full list of ingredients and measurements in the recipe card below.)

2 tablespoons unsalted butter
1 tablespoon olive oil
2 large yellow onions, thinly sliced
1 teaspoon sugar
½ teaspoon salt
3 garlic cloves, minced
1½ cups orzo pasta
2 cups cooked shredded chicken (rotisserie works well)
½ teaspoon dried thyme
¼ teaspoon black pepper
2 cups low‑sodium chicken broth
1 cup heavy cream (or half‑and‑half for a lighter option)
1½ cups shredded mozzarella cheese
½ cup grated Parmesan cheese
Optional: ½ teaspoon Worcestershire sauce or balsamic glaze for added depth

Directions

Preheat your oven to 375 °F (190 °C).
In a large oven‑safe skillet or Dutch oven, melt the butter and olive oil over medium‑low heat. Add the sliced onions, sugar and salt. Cook slowly, stirring occasionally, until the onions are deeply golden and caramelised (about 30‑40 minutes). Add the minced garlic for the last 1‑2 minutes.
While the onions cook, season the chicken with salt and pepper. Brown the chicken in a separate skillet (or after removing onions from the pan temporarily), just until golden on both sides (it will finish cooking in the oven).
Add the orzo to the onions and cook for about 2 minutes to lightly toast. Then stir in the browned chicken, thyme, pepper and Worcestershire sauce if using.
Pour in the chicken broth and heavy cream. Bring to a gentle simmer. Reduce heat to low, cover and cook for about 8‑10 minutes, stirring occasionally, until the orzo is tender but still has a little bite.
Remove the lid, stir in 1 cup of the mozzarella cheese and the Parmesan until melted and creamy.
Sprinkle the remaining ½ cup mozzarella over the top. Transfer the pan (if not already oven‑safe) to the preheated oven and bake uncovered for about 20‑25 minutes (or 10‑15 minutes depending on earlier orzo timing) until the top is golden and bubbly.
Let the casserole rest for 5‑10 minutes before serving to allow it to thicken slightly. Garnish with fresh thyme or chopped parsley if desired.

Servings and timing

Servings: 6
Prep Time: ~15 minutes
Cook Time: ~20 minutes on stovetop + ~20‑25 minutes baking

Variations

Vegetarian version: Skip the chicken and use sautéed mushrooms and spinach for a rich, meat‑less twist.
Add bacon: Stir in chopped, cooked bacon with the chicken for smoky flavour.
Make it spicy: Add a pinch of crushed red pepper flakes or chopped jalapeño when cooking the onions.
Gluten‑free: Use gluten‑free orzo or a short pasta alternative that holds up well in a casserole.
Low‑carb twist: Swap the orzo for cauliflower rice (note: baking time and liquid volumes may vary).

Storage/Reheating

Refrigerator: Store leftovers in an airtight container for up to 4 days. Reheat in the microwave or oven until hot.
Freezer: Let the casserole cool completely, then wrap tightly (either whole or in individual portions) and freeze for up to 2 months. Thaw overnight in the fridge before reheating.
Reheating tip: Add a splash of chicken broth or cream before reheating to keep it creamy and prevent drying out.

FAQs

1. Can I use chicken breasts instead of thighs?

Yes — chicken breasts will work fine, just be sure not to overcook them when browning since they’ll finish in the oven.

2. What if I don’t have Gruyère cheese?

You can substitute Swiss, provolone, or even mozzarella. For a sharper flavour, add a bit of Parmesan on top.

3. Can I use rotisserie chicken?

Absolutely. Shred about 2 cups of cooked rotisserie chicken and add it during the step where you stir in the chicken, skipping the browning process.

4. Can I make this ahead of time?

Yes — you can assemble the casserole up to the baking step, cover and refrigerate for up to 24 hours. Take it out of the fridge and let it come to room temperature before baking.

5. Is this casserole freezer‑friendly?

Yes — wrap it tightly once cooled and freeze for up to 2 months. Thaw overnight then bake until warmed through.

6. What if my orzo gets too soft or mushy?

Monitor the orzo’s doneness during the stovetop step. It should be tender but still slightly firm before baking, since it will absorb more liquid in the oven.

7. Can I use a different pasta instead of orzo?

Yes — you can use a small pasta shape like small shells or ditalini. Keep an eye on the liquid ratio and baking time, as different pastas absorb differently.

8. How can I make it dairy‑free or lighter?

You could use a dairy‑free cream alternative (such as oat or coconut cream) and a dairy‑free cheese substitute. Be aware the texture and flavour will vary.

9. Can I add vegetables to it?

Yes — adding vegetables like mushrooms, spinach, zucchini or peas works nicely. Saute them with the onions or stir them in during the liquid phase.

10. How do I reheat leftovers without drying them out?

Cover the casserole when reheating in the oven (or use a microwave‑safe covered dish) and add a splash of chicken broth or cream to restore the creamy texture.

Conclusion

This French Onion Chicken Orzo Casserole is a comforting, flavour‑packed dish that elevates simple ingredients into something special. With deeply caramelised onions, tender chicken, creamy orzo and melted cheese, it offers that restaurant‑quality feel while being easy enough for a weeknight. It also makes ahead and reheats beautifully. Try it once and you’ll likely reach for it again when you want a warm, satisfying, one‑dish dinner.