In a large pot, bring salted water to a boil. Add the elbow macaroni and cook according to package instructions until al dente, typically 7-9 minutes. Drain and set aside.

In a large skillet over medium heat, melt 1 tablespoon of butter. Add the diced chicken and season with salt, pepper, and 1 tablespoon of Cajun seasoning. Cook until golden brown and fully cooked, approximately 5-7 minutes. Remove and set aside.

In the same skillet, melt the remaining butter over medium heat. Whisk in the flour, stirring constantly for about 1-2 minutes until it forms a paste, or roux.

Gradually whisk in the milk, ensuring no lumps remain. Continue stirring until the sauce thickens, about 5 minutes. Once thick, add the cheeses and the remaining Cajun seasoning. Stir until melted and smooth.

Add the cooked pasta and chicken to the cheese sauce, stirring until well-coated. Taste and adjust seasoning if needed.

Preheat your oven to 350°F. Pour the mixture into a greased baking dish, top with additional cheese if desired, and bake for 20-25 minutes until bubbly and golden on top.

Let it sit for a few minutes before serving. Garnish with chopped parsley for a fresh kick!