**Preheat:** Preheat oven to 350°F (175°C).
**Cook Noodles:** Cook spaghetti or fettuccine according to package directions. Drain well and set aside.
1 pound spaghetti or fettuccine, cooked al dente
**Make Roux:** In a large saucepan, melt butter over medium heat. Whisk in flour until smooth. Cook for 1-2 minutes, stirring constantly.
1/2 cup butter, 1/2 cup all-purpose flour
**Add Broth and Milk:** Gradually whisk in chicken broth until smooth. Then, stir in milk. Bring to a simmer, stirring constantly until the sauce thickens.
4 cups chicken broth, 1 cup milk
**Season and Flavor:** Stir in Parmesan cheese and sherry (if using). Season with salt and pepper to taste.
1/2 cup Parmesan cheese, grated, 1/4 cup dry sherry (optional), Salt and pepper
**Combine Ingredients:** In a large bowl, combine cooked noodles, shredded chicken, and sauce. Mix well to ensure everything is evenly coated.
1 pound spaghetti or fettuccine, cooked al dente, 2 cups cooked chicken, shredded
**Prepare Topping:** In a small bowl, combine breadcrumbs, Parmesan cheese, and melted butter.
1/2 cup breadcrumbs, 1/4 cup Parmesan cheese, grated, 2 tablespoons melted butter
**Assemble and Bake:** Pour the chicken and noodle mixture into a greased 9x13 inch baking dish. Sprinkle the breadcrumb topping evenly over the top.
2 cups cooked chicken, shredded, 1 pound spaghetti or fettuccine, cooked al dente
**Bake:** Bake uncovered for 20-25 minutes, or until golden brown and bubbly.
**Cool and Serve:** Let stand for 5-10 minutes before serving. Enjoy your BEST Chicken Tetrazzini!
