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Spatula holding square of cheesy chicken spaghetti in white pan with the rest of the casserole.

Baked Cheesy Chicken Spaghetti

Yield: 6 to 8 servings
Prep Time: 25 minutes
Cook Time: 45 minutes
Total Time: 1 hour 10 minutes

Ingredients

  • 12 ounces spaghetti, broken in half
  • 1 ¾ cups milk (preferably not skim; recipe works best with 1%, 2% or whole milk)
  • 1 ½ cups chicken broth or stock
  • ¼ cup + 2 tablespoons all-purpose flour
  • 2 tablespoons salted butter
  • 1 teaspoon onion powder
  • 1 teaspoon garlic powder
  • 1 teaspoon dried basil
  • ½ teaspoon dried oregano
  • ¾ teaspoon table salt
  • ⅛ teaspoon black pepper
  • ⅛ teaspoon dried thyme
  • ¾ cup grated Parmesan cheese, divided (see note)
  • 2 ½ cups shredded medium or sharp cheddar cheese, divided (see note)
  • 3 cups cooked, chopped chicken
  • Chopped fresh parsley, for garnish, optional

Instructions 

  • Preheat the oven to 375 degrees F. Lightly grease a 9X13-inch baking pan. Set aside.
  • In a large pot of lightly salted boiling water, cook the spaghetti according to package directions until al dente. Drain and set aside (lift and separate the noodles a few times so they don't stick as they cool). Don't wash out the pot; just wipe dry, if needed.
  • Add the milk, broth, and flour to a blender and process until smooth. Set aside.
  • Return the pot to medium heat. Melt the butter and add the onion powder, garlic powder, basil, oregano, salt, pepper and thyme. Cook for 30-45 seconds, stirring often until the spices are sizzling and smell fragrant.
  • Pour the milk mixture into the pot and bring to a simmer, whisking constantly. Continue cooking for 3 to 4 minutes until thickened.
  • Remove the pot from the heat and add 1/2 cup of the Parmesan cheese and 2 cups of the cheddar cheese to the sauce (reserve the rest of the cheese for topping). Stir until the cheese has melted. Season to taste with additional salt and pepper (important!).
  • In a large bowl (or back into the pot, if you prefer), add the cooked spaghetti and chicken. Toss and stir until the noodles and chicken are evenly coated with the sauce.
  • Spread the pasta mixture evenly in the prepared pan. Sprinkle the remaining cheeses over the top.
  • Bake for 20 to 25 minutes until hot and bubbly. Serve warm.

Notes

Seasonings: in place of the basil, oregano and thyme, you can sub in 1 1/2 to 1 3/4 teaspoons Italian seasoning.
Cheese: if you have the time, freshly grate block cheese for this recipe (vs using pre-shredded cheese which is coated with a powder substance to prevent it from clumping; but it also prevents it from melting as well). I like to grate the Parmesan on the small holes of the box grater, and I use the large holes of the box grater for the cheddar cheese.
Make-Ahead: this chicken spaghetti can be assembled the night before or the morning of to bake later in the day. It can also be frozen prior to baking. To bake, thaw overnight in the refrigerator and bake, covered, for 45 minutes, then uncover, and bake for a few minutes longer until hot and bubbly.