7 tablespoons butter, divided
5 tablespoons flour
2 cups chicken stock
3 cups half-and-half
1 teaspoon garlic powder
½ teaspoon black pepper
½ teaspoon crushed red pepper flakes
2 cups grated Parmesan cheese, divided
1 cup mascarpone cheese
1 pound spaghetti
2 cups shredded rotisserie chicken
1 cup shredded mozzarella cheese, divided
1/2 cup Italian breadcrumbs
Preheat the oven to 350F. Grease a 9-by-13-inch casserole dish.
Melt 5 tablespoons of butter over medium-low heat in a saucepan. Add the flour, and whisk together to make a roux, cooking one to two minutes, until thick. Drizzle in the chicken stock by the quarter cupful, whisking well after each addition. When all of the chicken stock has been added, bring the sauce to a simmer, then remove from the heat. The sauce should be thick enough to coat the back of a wooden spoon.
Whisk in the garlic powder, black pepper, red pepper flakes, 1 ½ cups of the Parmesan, and the mascarpone. Stir until smooth, return it to the heat, and add the half-and-half.
Stir until smooth, then set aside.
Cook the spaghetti according to package directions. Drain the spaghetti, and transfer it to a large mixing bowl, along with the shredded rotisserie chicken. Add the sauce to the bowl, tossing well with tongs. Add half of the mozzarella cheese, and toss to combine.
Transfer the mixture to the casserole dish. In a bowl, combine the breadcrumbs with the remaining mozzarella and Parmesan. Sprinkle the mixture over the top of the casserole.
Break the remaining butter into small, pea-sized bits, and sprinkle evenly over the top of the casserole.
Bake for 25 minutes, until bubbly and brown.
