Description

This French Onion Chicken Orzo Casserole is a comforting, creamy one-pan dish combining deeply caramelized onions, tender shredded chicken, and tender orzo pasta all baked to perfection under a layer of melted Gruyère and mozzarella cheese. Rich beef and chicken broths enhance the classic French onion flavor while the addition of cream and herbs make for a luscious, crowd-pleasing casserole that’s perfect for weeknight dinners or special occasions.

Ingredients

Scale

For the Caramelized Onions

2 large yellow onions, halved and thinly sliced (about 5–6 cups sliced)
2 tbsp unsalted butter
1 tbsp olive oil
1 tsp kosher salt, divided (½ at the start, ½ later)
¼ tsp black pepper
1 tsp sugar (optional)
Optional flavor boosters: 1–2 tbsp dry white wine, ½ tsp balsamic vinegar, ½ tsp Worcestershire sauce

For the Casserole Base

1 ½ cups uncooked orzo
2 cups shredded cooked chicken (rotisserie or leftover roasted is ideal)
2 cups beef broth
1 cup chicken broth
½ cup heavy cream (or half-and-half for lighter option)
1 tbsp Worcestershire sauce
2 cloves garlic, minced
1 tsp dried thyme or 1½ tsp fresh thyme leaves
½ tsp onion powder
Additional salt & pepper, to taste

Cheese Topping

1 ½ cups shredded Gruyère cheese
½ cup shredded mozzarella cheese
Optional: ¼ cup finely grated parmesan cheese for browning and sharpness

Optional Garnishes

Fresh thyme sprigs
Parsley
Crispy fried onions
A drizzle of cream or dollop of sour cream
Fresh cracked black pepper

Instructions

Caramelize the onions: Heat butter and olive oil in a large oven-safe skillet over medium heat until butter melts and begins to foam. Add all sliced onions and sprinkle with ½ tsp salt. Stir occasionally for 5–8 minutes as onions soften and release moisture. Reduce heat to medium-low and add sugar if using. Continue to stir every few minutes for 10–20 minutes until onions develop a deep golden brown color and jammy texture. Adjust heat to avoid burning. Optionally, deglaze the pan with white wine, balsamic vinegar, or Worcestershire sauce, cooking until liquid nearly evaporates. Add remaining salt, black pepper, and minced garlic; cook for 1 minute until fragrant. The onions should be soft, sweet, and reduced to about 1½–2 cups.
Toast the orzo: Add the uncooked orzo directly into the caramelized onions. Stir to coat the orzo with the butter and onion mixture. Toast for 1–2 minutes until the orzo emits a nutty aroma. This step prevents mushiness and enhances texture.
Add liquids, chicken, and seasonings: Pour in the beef broth and chicken broth, stirring well to loosen any browned bits from the pan. Stir in the heavy cream. Fold in the shredded cooked chicken evenly throughout the mixture. Add Worcestershire sauce, thyme, onion powder, and season with fresh black pepper. Taste and adjust salt as needed.
Bring to a simmer: Increase heat to medium-high and allow the mixture to come to a gentle simmer, with bubbling around the edges but not a full rolling boil. Once simmering, turn off the heat.
Bake the casserole: Cover the skillet tightly with its lid or aluminum foil. Place in the preheated oven at 400°F (205°C) and bake for 18–22 minutes until the orzo is tender, creamy, and most of the liquid is absorbed. If the casserole appears watery, bake uncovered for an additional 3–5 minutes. Remove from oven and sprinkle the Gruyère and mozzarella cheese evenly on top; optionally add parmesan for extra browning and flavor. Return to oven briefly to melt and brown cheese if desired.
Garnish and serve: Once baked, garnish with fresh thyme sprigs, parsley, crispy fried onions, a drizzle of cream or dollop of sour cream, and fresh cracked black pepper as preferred. Serve warm and enjoy this rich, comforting casserole.

Notes

Caramelizing onions properly is key for deep flavor—be patient during this step.
Using rotisserie or leftover roasted chicken saves time and adds great flavor.
To reduce richness, substitute half-and-half for heavy cream.
Deglazing with wine, balsamic, or Worcestershire sauce boosts depth of flavor.
Toast orzo before adding liquid to improve texture and prevent mushiness.
If casserole is too watery after baking, continue baking uncovered to thicken.
Gruyère cheese gives a classic French onion flavor but mozzarella helps with melting; parmesan is optional for sharpness and browning.

Prep Time: 20 minutes
Cook Time: 45 minutes
Category: Casserole
Method: Baking
Cuisine: French-American

Keywords: French onion chicken casserole, orzo casserole, caramelized onions, baked chicken pasta, comfort food casserole