Bring a large pot of salted water to a boil. Add the penne pasta and cook for 10-12 minutes, stirring occasionally, until al dente. Drain well and set aside.

In a large skillet, heat 2 tablespoons of olive oil over medium heat. Season the chicken breast with Cajun seasoning and sauté for 4-5 minutes until golden brown.

Add the shrimp to the skillet and cook for 2-3 minutes until pink and opaque, then remove and set aside.

Add another tablespoon of olive oil, followed by the sliced sausage. Sauté for about 2 minutes, then add bell peppers, red onion, and garlic. Cook for approximately 4 minutes.

Pour in the heavy cream and bring to a gentle simmer for 2-3 minutes. Stir in Parmesan cheese until melted, and adjust seasoning with salt, pepper, and Cajun seasoning.

Return chicken and shrimp to the skillet, followed by the cooked pasta. Toss everything together for 1-2 minutes over low heat until fully coated.

Sprinkle chopped parsley over the top and serve immediately, either plated or in a large bowl.