Chicken Spaghetti

Preparation

1. Step 1

   Heat the oven to 350 degrees with the rack in the center position. Butter a 9-by-13-inch casserole dish. Bring a large pot of well salted water to a boil. Add the spaghetti and cook until just shy of al dente, about 9 minutes. Drain and transfer to a large mixing bowl.

2. Step 2

   Meanwhile, in a large pan, melt the butter over medium heat. Add the onion, mushrooms, celery and bell pepper. Cook, stirring occasionally, until softened, 10 to 12 minutes. Add the garlic, season with salt and pepper, and cook, stirring occasionally, for 2 minutes. Stir in 2 tablespoons of the flour until smooth; repeat with the remaining flour, continuously stirring until the flour releases a nutty aroma, about 2 minutes.

3. Step 3

   Slowly pour in the milk, ¼ cup at a time, stirring continuously so there are no lumps. Slowly pour in the chicken stock, stirring continuously. Add the onion powder, garlic powder, 1 teaspoon salt and ½ teaspoon black pepper. Stir continuously, until thickened, about 5 minutes. Stir in the tomatoes, taste for seasoning and remove from the heat.

4. Step 4

   Add the saucy vegetable mixture, chicken, 1 cup of the Cheddar and the Parmesan to the spaghetti and toss well to combine. Taste, adjust seasoning, and add hot sauce, if you like. Transfer the spaghetti mixture to the prepared casserole dish, spreading it out evenly and topping with the remaining Cheddar. Bake, uncovered, until the cheese melts and the casserole is bubbling, about 40 minutes. Remove from the oven and let cool for 5 minutes before serving.