Step 1: Cook the Pasta
Bring a large pot of salted water to a boil. Cook the pasta according to package instructions until al dente. Reserve 1/2 cup of the pasta water, then drain and set aside.

Step 2: Season the Shrimp and Chicken
In a bowl, combine shrimp and chicken with Cajun seasoning, smoked paprika, garlic powder, salt, and pepper. Toss to coat evenly.

Step 3: Sear the Shrimp and Chicken
Heat 1 tablespoon of olive oil and 1 tablespoon of butter in a large skillet over medium heat. Cook the chicken pieces for 4-5 minutes per side until golden brown and fully cooked. Remove and set aside. In the same skillet, add the shrimp and cook for 2-3 minutes per side until pink and opaque. Remove and set aside with the chicken.

Step 4: Sauté the Vegetables
In the same skillet, add the remaining olive oil and butter. Sauté the diced onion, garlic, and bell pepper for 3-4 minutes until softened and fragrant.

Step 5: Create the Sauce
Pour in the chicken broth, scraping the bottom of the skillet to deglaze. Stir in the heavy cream and Parmesan cheese. Reduce the heat to low and let the sauce simmer for 5-7 minutes until slightly thickened. Add red pepper flakes if you prefer more heat.

Step 6: Combine Pasta, Protein, and Sauce
Return the cooked shrimp and chicken to the skillet, tossing them in the sauce. Add the cooked pasta and reserved pasta water if needed to achieve your desired consistency. Mix until everything is well coated in the creamy Cajun sauce.

Step 7: Serve and Garnish
Transfer the pasta to plates or bowls. Garnish with freshly chopped parsley and additional Parmesan cheese.