Step 1: Preheat your oven to 375°F (190°C). Lightly grease a 9×13-inch baking dish and set it aside.

Step 2: Bring a large pot of salted water to a boil. Add the penne pasta and cook according to the package instructions until al dente, about 10–11 minutes. Drain and set aside.

Step 3: While the pasta cooks, heat olive oil in a large skillet over medium-high heat. Season the chicken cubes with Cajun seasoning, smoked paprika, garlic powder, salt, and pepper. Add the chicken to the skillet and cook until browned and cooked through, about 6–8 minutes. Remove the chicken from heat.

Step 4: In a separate saucepan, melt the butter over medium heat. Add the minced garlic and sauté for about 1 minute until fragrant. Stir in the flour and cook for 1 minute more to form a light roux.

Step 5: Slowly pour in the milk while whisking continuously to avoid lumps. Let the mixture simmer gently for 4–5 minutes, until it thickens.

Step 6: Stir in the Parmesan, 1½ cups mozzarella, and sour cream (or cream cheese). Add red pepper flakes if you want a little heat. Mix until the cheeses melt and the sauce is creamy. Taste and adjust salt and pepper.

Step 7: In a large bowl or right in your baking dish, combine the cooked penne, Cajun chicken, and creamy sauce. Stir until everything is evenly coated.

Step 8: Transfer to the baking dish (if you haven’t already) and sprinkle the remaining ½ cup of mozzarella cheese over the top.

Step 9: Bake uncovered for 20–25 minutes, until the top is bubbly and golden brown.

Step 10: Remove from oven, garnish with chopped parsley if desired, and let it rest for a few minutes before serving.