Bring a large pot of salted water to a rolling boil. Add the penne pasta and cook until al dente, about 10 to 12 minutes. Drain and set aside.

In a large skillet, heat 2 tablespoons of olive oil over medium-high heat. Season chicken with Cajun seasoning, add to skillet, and cook for 4-5 minutes on each side until golden brown. Remove from skillet.

In the same skillet, add shrimp and cook for 2-3 minutes until pink and opaque. Remove shrimp and mix with chicken.

Add another tablespoon of olive oil to the skillet, sauté andouille sausage for about 2 minutes. Then add bell peppers, red onion, and garlic, cooking for another 4 minutes until veggies are tender.

Pour heavy cream into skillet, reduce heat to medium-low, and let simmer for 2-3 minutes. Gradually stir in Parmesan cheese until melted. Adjust seasoning with salt and pepper.

Return chicken and shrimp to skillet, add the drained penne pasta, and gently toss to coat in the sauce. Heat through for 1-2 minutes.

Remove from heat, sprinkle with chopped parsley, and serve immediately.