This simple five ingredient pasta casserole recipe for chicken manicotti tastes like you spent all day making it. Chicken and spinach alfredo manicotti is creamy, filling, and sneaks in your green vegetables Its super easy to make and is so full of flavor. The alfredo sauce is homemade, but it comes together in only a few steps and is so creamy and garlicky. We used leftover rotisserie chicken to speed up the process. Feel free to use any leftover chicken you have. Or you can grill or poach the chicken prior to preparing this recipe. You can easily make this dish vegetarian by leaving out the chicken, simply increase the amount of spinach and ricotta cheese so you have enough to fill all of the noodles. Try splitting this dish into two containers and freezing one before baking. Once youre ready to eat, serve it alongside your favorite salad and some breadsticks, for sopping up the delicious sauce.