Ingredients

Cooking spray

3 tablespoons unsalted butter

1 cup diced yellow onion (from 1 medium onion)

2 teaspoons kosher salt, divided

3 tablespoons all-purpose flour

1 3/4 cups low-sodium chicken broth

1/2 cup whole or 2% milk

3/4 teaspoon freshly ground black pepper, divided

3/4 cup uncooked long-grain white rice

3 cups frozen mixed vegetables, such as carrots, corn, peas, and green beans

1 1/2 pounds boneless, skinless chicken thighs, trimmed of excess fat

1/2 cup shredded cheddar cheese (4 ounces)

Hot sauce, for serving

Instructions

Step 1: Arrange a rack in the middle of the oven and heat the oven to 375°F. Coat an 11×7-inch or 1 1/2-quart baking dish with cooking spray and set aside.

Step 2: Melt 3 tablespoons unsalted butter in a large skillet over medium heat. Add 1 cup diced yellow onion and 1 1/2 teaspoons kosher salt. Sauté until the onion is soft but not browned, about 3 to 5 minutes.

Step 3: Sprinkle in 3 tablespoons all-purpose flour and cook for 1 minute, stirring constantly to coat the flour in the butter and cook off the raw flour flavor.

Step 4: Pour in 1 3/4 cups low-sodium chicken broth and whisk to incorporate, breaking up any lumps and scraping browned bits from the pan. Add 1/2 cup milk and 1/4 teaspoon black pepper, whisking to combine.

Step 5: Bring the sauce to a boil, stirring constantly, and cook until thickened, about 3 minutes.

Step 6: Place 3/4 cup uncooked long-grain white rice and 3 cups frozen mixed vegetables in the prepared baking dish. Pour the sauce over the rice and vegetables and stir to combine.

Step 7: Season chicken thighs with the remaining 1/2 teaspoon kosher salt and 1/2 teaspoon black pepper. Nestle the chicken on top of the rice mixture. Cover the baking dish tightly with aluminum foil.

Step 8: Bake for about 1 hour, until the rice is tender and an instant-read thermometer inserted into the thickest part of the chicken registers 160°F.

Step 9: Turn the oven off. Uncover and sprinkle the casserole with 1/2 cup shredded cheddar cheese. Return to the warm oven uncovered and let sit until the cheese melts, 2 to 4 minutes.

Step 10: Serve hot with optional hot sauce for a spicy kick.

Tips & Variations

Use chicken breasts instead of thighs for a leaner option, but baking time may vary.

Swap frozen mixed vegetables with fresh seasonal veggies for added freshness and texture.

For a creamier casserole, stir in a dollop of sour cream or cream cheese before baking.

Add herbs like thyme or parsley for extra flavor in the sauce.

Use low-fat cheese or a blend of cheeses if you prefer a different taste.

FAQs

Can I make this casserole ahead of time?

Yes, you can prepare the casserole up to Step 7, then cover and refrigerate for up to 24 hours before baking. Just add extra baking time if baking straight from cold.

Can I use brown rice instead of white rice?

You can use brown rice, but it will require a longer cooking time and more liquid. It’s best to partially cook the brown rice before adding it to the casserole to ensure it cooks fully.