Season and Cook Chicken. Rub Cajun seasoning onto butterflied chicken breasts. Cook in olive oil for 3-4 minutes on each side until golden and cooked through. Slice into strips.
Prepare Alfredo Sauce. In the same pan, melt butter and sauté garlic. Add heavy cream, Parmesan, salt, and pepper. Stir until the cheese melts and the sauce thickens.
Cook Pasta. Cook fettuccine pasta according to package instructions. Drain.
Combine and Serve. Toss the cooked pasta and Cajun chicken strips into the Alfredo sauce. Mix until well coated. Serve hot, garnished with fresh parsley.