Boil the pasta following the directions on the box. Drain and rise with cold water. Set aside until needed. Cook the chicken: You can sauteed the chicken in a skillet or grill the chicken, use rotisserie chicken or even use leftover chicken.
In a large skillet, sauté the minced garlic for one minute. Sprinkle the flour into the butter and whisk until a thick lump free paste forms. Drizzle the whipping cream in while whisking to blend the flour and butter roux into the cream. Whisk in the Parmesan cheese.
Bring the alfredo sauce to a low boil to thicken while whisking occasionally. Once the alfredo sauce is boiling add the baby spinach leaves to the skillet in handfuls while stirring it into the alfredo sauce. Add the cooked chicken to the pan and fold the bite size pieces into the sauce.
Continue stirring until the chicken warms up. Remove the skillet from the burner toss the fettuccine noodles with the chicken spinach alfredo sauce. Once all of the pasta is mixed into the sauce serve immediately. Top with more shredded cheese, minced parsley and red pepper flakes.