Season the chicken breast in a little cajun seasoning on both sides, and cook it in a little oil until both sides and nice and brown. If the chicken isn't 100% cooked through at this point, don't worry. You can finish cooking it in the sauce later as it simmers. Slice the chicken into pieces and set aside.
Slice the sausage and chop the onion, garlic, bell peppers. Use any color bell pepper or a combination. I like slicing the peppers and then rough chopping some of them for texture.
In the same pan you cooked the chicken, brown the sausage. Add a little oil if needed. Add onion, bell peppers, garlic and continue to sautee the vegetables until they start to soften. Add chili flakes (if using), cajun seasoning, then cream, cream cheese, and stock. Bring to a simmer. If the chicken is under-cooked from before, add it now to finish cooking it. The sauce will thicken as it simmers, about 5 mins. Taste, and season with salt & pepper to taste.
Cook your prefered pasta (parpadelle, fettucini, buccatini, farfalle, penne, rigatoni are all excellent for this dish) per package instructions to a little under al dente. Toss the cooked pasta in the sauce until coated. The pasta will continue to cook a couple minutes more in the sauce. This will also help the sauce thicken, as the pasta absorbs the liquid and introduces starch.
Top with chopped parsley and parmesan, and serve!