Heavily adapted from: http://www.gimmesomeoven.com/chicken-alfredo-baked-ziti-recipe/

For the Casserole:
12 oz. GF Shaped Pasta (I used Tinkyada Shells)
At least 2 cups shredded cooked chicken
Batch GF Alfredo Sauce
16oz. shredded mozzarella
Freshly Grated Parmesan

For the Alfredo:
2 tbs. olive oil
4 cloves garlic, freshly minced
3 tbs. GF Flour (I used Better Batter)
1 cup milk
1 cup chicken broth
3/4 cup freshly grated parmesan
Salt and Pepper

1. Preheat oven to 375. Boil water and cook GF pasta until al dente, or slightly shorter than package directions. Drain and return to pot.
2. While pasta cooks, saute garlic in olive oil one or two minutes, until fragrant. Sprinkle evenly with the flour and cook one more minute, stirring constantly to prevent burning.
3. Whisk in milk and then chicken broth and then bring to a simmer until the mixture thickens. You will be able to dip a spoon into it and the sauce will just barely stick to the spoon instead of running off when finished. Stir in parmesan and salt and pepper and let melt completely. Turn off burner.
4. In the pot with the drained pasta, combine pasta, chicken, and Alfredo sauce. Toss to coat.
5. In a greased 9X13 casserole dish, layer half of the pasta, then 1 cup of cheese, then the other half of pasta and 1 cup of cheese. Bake for 25 minutes until the cheese is golden and bubbly.
6. Remove from oven and top with chopped parsley and parmesan if desired.