01 - Bring a large pot of salted water to a boil. Cook the pasta according to package directions until al dente. Drain, reserving 1/2 cup pasta water.
02 - Butterfly the chicken breasts for even thickness. Pat dry and rub both sides with olive oil.
03 - In a small bowl, combine Cajun seasoning, smoked paprika, garlic powder, onion powder, cayenne, salt, and pepper. Rub mixture evenly over both sides of the chicken.
04 - Heat a large skillet over medium-high heat. Add the chicken and cook 4–5 minutes per side, until blackened and cooked through (internal temperature should reach 165°F). Remove to a plate, tent with foil, and rest for 5 minutes.
05 - In the same skillet, add butter over medium heat. Sauté garlic until fragrant, about 1 minute.
06 - Add heavy cream and bring to a gentle simmer. Stir in Parmesan, black pepper, and nutmeg. Simmer gently until sauce is smooth and slightly thickened, 3–4 minutes. Season with salt to taste. If sauce is too thick, add reserved pasta water a little at a time.
07 - Toss the cooked pasta with the Alfredo sauce until well coated.
08 - Slice the blackened chicken and arrange on top of the pasta. Sprinkle with chopped parsley and extra Parmesan before serving.