Cook the pasta according to the package directions. Drain and set aside.
Season the chicken breasts with Cajun seasoning.
Heat 1 tablespoon of olive oil in a large pan over medium heat. Lay the chicken flat and cook each side for 3-4 minutes until cooked through. Remove to a cutting board and cut into thin slices.
Add the remaining 1 tablespoon of olive oil to the pan. Add the onions and garlic and saute for 4 minutes until softened. Add the tomato paste and cook for 30 seconds.
Add the heavy cream and bring to a boil. Reduce to a simmer and let it bubble for 2 minutes. Add the parmesan, chicken, and pasta to the pan. Mix and cook until the sauce thickens to your liking. If you accidentally make the sauce too thick, just add some water.
Nutrition information is calculated using an ingredient database and should be considered an estimate.