Season the chicken

• Pat the chicken breasts dry and season them liberally with the Cajun seasoning on both sides.

Blacken the chicken

• Sear the chicken in a very hot skillet until blackened and cooked through, turning once.
• Add part of the butter toward the end of cooking for maximum juiciness.
• Remove the chicken from the pan and set aside.

Start the Alfredo sauce

• In the same pan, melt the remaining butter and add the garlic.
• Whisk in the heavy cream and Parmesan.
• Simmer gently until the sauce thickens slightly.

Cook the pasta

• Boil the fettuccine in salted water until al dente.
• Drain, reserving a little pasta water.

Combine and serve

• Toss the pasta into the Alfredo sauce to coat, loosening with pasta water if needed.
• Slice the chicken and arrange it on top of the Alfredo.