Cook pasta according to package directions, reserving 1 cup of starchy cooking water. Drain and return to hot pot, add chopped spinach, cover and set aside to let spinach to wilt.
Heat olive oil over medium – high heat in a large skillet.
Once hot, add chicken to the skillet and saute for approximately 5 minutes, or until chicken is cooked thorugh.
Add onion and garlic to the pan and saute for 2-3 minutes or until the onion has softened and beginning to turn translucent.
Add cream cheese and reserved cooking water to chicken. Stir to combine and melt cream cheese.
Add chicken mixture to pot with the pasta and spinach. Add parmesan, crushed pepper, salt and pepper. Stir to combine.
Serve with additional parmesan cheese and additional red pepper flakes to garnish.