01 - Bring a large pot of salted water to a boil. Cook fettuccine according to package instructions until al dente. Reserve ½ cup pasta water, then drain and set aside.
02 - While the pasta cooks, pat chicken breasts dry. Rub both sides with Cajun seasoning, salt, and black pepper.
03 - Heat olive oil in a large skillet over medium-high heat. Add chicken breasts and cook 5–6 minutes per side, or until blackened and cooked through (internal temp 165°F). Remove chicken to a plate, tent loosely with foil, and let rest.
04 - In the same skillet, reduce heat to medium. Add butter and melt, scraping up browned bits. Add minced garlic and sauté 1 minute until fragrant.
05 - Pour in heavy cream. Simmer 2–3 minutes. Gradually whisk in Parmesan cheese until melted and sauce thickens. Season with black pepper, nutmeg (if using), and salt to taste.
06 - Toss drained fettuccine in the Alfredo sauce, adding reserved pasta water a bit at a time for desired consistency.
07 - Slice blackened chicken breast and arrange atop the sauced pasta. Garnish with parsley and extra Parmesan. Serve immediately.