Bring a large pot of salted water to a boil. Add the penne pasta and cook according to package instructions until al dente, about 10-12 minutes. Reserve ½ cup of pasta water before draining.

In a mixing bowl, toss chicken pieces with Cajun seasoning, salt, and pepper. Heat oil in a large skillet over medium-high heat, add chicken, and cook for 5-7 minutes until golden brown.

In the same skillet, reduce heat to medium and melt butter. Add chopped onion, minced garlic, and diced bell pepper, sauté for 2-3 minutes until soft.

Deglaze the pan with ½ cup of white wine or chicken broth, scraping up bits stuck to the bottom. Simmer for 2 minutes.

Stir in 1 cup of double cream and ½ cup of grated Parmesan. Simmer gently for 2-3 minutes until the sauce thickens.

Lower heat and return cooked pasta and chicken to the skillet, tossing everything together in the creamy sauce. Add reserved pasta water as needed.

Remove from heat and garnish with freshly chopped parsley before serving hot.