Cook fettuccini noodles according to package directions, drain and set aside while preparing alfredo sauce.
Place butter, cream cheese and heavy cream into a large rimmed pan over medium heat. Using a whisk, gently stir and cook until melted and smooth, be patient this takes 5-8 minutes. Mixture will thicken as well. When creamy, whisk in Parmesan, salt and pepper to combine. Reduce heat to simmer, stirring often.
Place warm cooked noodles and warm chicken in individual serving bowls. Spoon hot sauce over top, stir and serve. Garnish with fresh chopped parsley if desired.
Notes
Don't overcook your pasta. Whether you're using fresh or dry fettuccine or other noodles of your choice, be very cautious not to overcook the pasta. I generally drain the pasta 1 minute before the package says cook time is. Pasta will continue to cook in hot alfredo sauce too. You want the noodles to be al dente. Al dente (Italian for “to the tooth”) is where pasta tastes and feels the best. It's chewy and firm, holding its whole shape in whatever sauce you put it in.
What kind of chicken to use? Grilled chicken strips are perfect with chicken alfredo, but you can also use shredded chicken pieces from a rotisserie chicken as I've done in mine. Quick and simple alternative.
What can I add to my pasta? Try adding meatballs for another variation with your alfredo sauce. Try adding bacon crumbles too. More variations could be cooked shrimp, add some vegetables such as asparagus and broccoli.