In a small bowl, combine all the Cajun seasoning ingredients and mix well.
Season the chicken pieces with 2-3 tablespoons of the Cajun seasoning mixture. Make sure the chicken is well coated. Set aside for at least 10 minutes to marinate.
Cook the penne pasta according to the package instructions until al dente. Drain and set aside.
Heat the olive oil in a large skillet or pan over medium-high heat. Add the marinated chicken pieces and cook until they are browned and cooked through, about 4-5 minutes per side. Remove the chicken from the pan and set it aside.
In the same pan, add the chopped onions and bell peppers. Sauté until they become soft and slightly caramelized, about 3-4 minutes.
Add the minced garlic and cook for another 30 seconds to 1 minute until fragrant.
Stir in the diced tomatoes, heavy cream, and chicken bouillon. Bring the mixture to a simmer and let it cook for about 2-3 minutes.
Reduce the heat to low and return the cooked chicken to the pan. Allow the mixture to simmer for an additional 2-3 minutes to heat the chicken through.
Stir in the grated Parmesan cheese and cook until the sauce thickens and the cheese is melted and creamy.
Season with salt and pepper to taste.
Add the cooked penne pasta to the sauce and toss everything together until the pasta is well coated with the creamy Cajun sauce.
Garnish with chopped fresh parsley.
Serve the Cajun Chicken Penne Pasta hot, and enjoy your delicious meal!