Boil water in a large pot. Add the rotini pasta and cook according to package instructions until al dente. Drain and set aside.

In a large bowl, combine peeled shrimp and diced chicken with Cajun seasoning until evenly coated.

Heat olive oil in a large skillet over medium-high heat. Add the seasoned chicken and cook until browned, about 6-7 minutes. Remove and set aside.

In the same skillet, melt butter, add minced garlic, and sauté for 1-2 minutes until fragrant. Add shrimp and cook for about 3-4 minutes on each side until pink and opaque. Remove and set aside.

Reduce heat to medium and pour in heavy cream and milk. Stir to combine and bring to a simmer. Reduce to low heat and stir in cheeses, smoked paprika, red pepper flakes if using, and salt. Stir until cheese melts and sauce is smooth.

Return chicken and shrimp to the skillet, then add cooked pasta. Toss until evenly coated in the creamy sauce.

Sprinkle with freshly chopped parsley before serving.