In a gallon zipper style bag, combine the chicken, ONE tablespoon of the olive oil and Cajun seasoning. Shake or knead the bag to evenly coat the chicken.
In a large fry, grill or saute pan, heat remaining one tablespoon of olive oil over medium high heat. Once heated, place chicken breasts in pan, and cover. Flip chicken breasts after approximately seven minutes, cooking for a total of seven minutes on EACH side. * Note that different sizes of chicken breasts may require more or less cooking time.
Start pasta and cook according to package directions.
In a heavy, medium sized saucepan, melt butter over medium heat. Whisk in flour, stirring until well combined and mixed in with the butter. Add the cream cheese and garlic. It will get a little lumpy, but whisk until all ingredients are incorporated. Add in 1/4 of the half and half and whisk until very well combined. Add in Parmesan cheese and stir well. Slowly whisk in remaining half and half, and bring to a gentle boil, whisking almost continuously. It will need to hit the boiling point before it starts to thicken up. If desired, add salt, pepper and additional Cajun seasoning.
Pour sauce over drained pasta and stir to combine.
Serve immediately. Chicken can be sliced and added to the pasta or placed on top of the pasta. Garnish with tomatoes and/or green onions if desired.
Enjoy!