Pimentos and green chilies combine with cheddar cheese and tarragon to give Cheddar Chicken Spaghetti casserole its unique flavor. Tarragon is one of my favorite herbs to combine with chicken—the flavors are fabulous together.
Combine chicken, 1 cup cheese, soup, milk, pimientos, green chilies, tarragon, salt, and pepper.
Add spaghetti and mix gently. Place mixture in a greased 13 x 9 x 2 baking dish and top with the remaining cheese.
Bake uncovered at 350°F for 20-25 minutes or until heated through.
The casserole freezes well so if you want to double up on the recipe, it's a good dish to stock the freezer. To freeze, assemble the casserole in a freezer-safe container, but do not bake. Cover with foil or freezer paper and label with "Cheddar Chicken Spaghetti: Thaw and bake at 350ºF for 20-25 minutes."