When it's time to eat, Chicken Spaghetti is comfort food that delights everyone. This easy recipe is a heavenly combination of noodles, chicken, and red peppers in a creamy sauce, with lots of melted cheese.
Preheat oven to 400 degrees. In a large pot, bring 4 quarts water and 1 tablespoon salt to boil. Add spaghetti and cook until al dente, about 9 to 10 minutes. Drain well.
Meanwhile, in a large skillet over medium-high heat, heat olive oil until shimmering. Add onion and bell pepper and cook until softened, about 5 minutes.
Add chicken and chili powder and season to taste with salt and pepper (I like 1 teaspoon salt and 1/2 teaspoon pepper). Cook until chicken is golden brown, about 5 to 7 minutes. Transfer chicken and vegetable mixture to a bowl.
Return the Dutch oven to medium-high heat and melt butter. Whisk in flour and cook until lightly browned, about 1 minute. Whisk in milk and chicken broth and cook until thickened, about 3 to 5 minutes.
Season to taste with salt and pepper (I like 1 teaspoon salt and 1/2 teaspoon pepper). Do not skip this step or your casserole may be bland!
Stir in 1 cup cheddar cheese. Add cooked spaghetti and chicken and vegetable mixture and toss until well combined. Transfer to a 3-quart or larger baking dish and top with remaining 1 cup of cheese.
Bake until hot and bubbly, about 20 to 25 minutes (a chicken piece should register 165 degrees on an internal thermometer). Let stand 5 minutes before serving. Garnish with fresh parsley if desired.
Spaghetti: Or use something more forkable, like penne or ziti.
Chicken: I always use boneless, skinless chicken thighs, but you can use chicken breasts, leftover rotisserie chicken, or even leftover turkey.
Yield: This recipe makes about 12 cups of casserole, enough for 8 generous servings (1 1/2 cups each) or more if you're serving it at a potluck or as part of a buffet with other main dish options.
Storage: Store leftovers covered in the refrigerator for up to 4 days.
Make ahead: Make up to 2 days before you need it; store covered in the refrigerator.
Freezer: Cover, wrap, and freeze the unbaked casserole. Thaw overnight in the fridge and bake in a 400 degree oven until heated through.
Season at every step: I like to salt and pepper at several stages, just to layer the seasoning and make the flavors really pop. If you don't season the sauce, the casserole will be bland.
Foil: Everyone's oven is a little different. If yours runs hot, cover the casserole with foil to protect the cheese from burning.
More vegetables: Add or substitute sliced button mushrooms, canned green chilies, scallions, diced tomatoes, blanched broccoli florets, or olives.
Crumb topping: If you love crunch, toss bread crumbs, cracker crumbs, or even cornflakes in melted butter and sprinkle on top of the casserole before baking.
Spicy: If you crave spicy foods, add diced jalapeños or serranos to the sauce with the chicken, and serve with plenty of hot sauce on the side.