Boil a large pot of salted water and cook fettuccine according to package instructions until al dente.
Toss chicken strips with cajun seasoning until evenly coated.
Heat olive oil in a large skillet over medium-high heat, add chicken, and sear until cooked through (internal temperature 165°F). Remove and set aside.
In the same skillet, melt butter over medium heat, add garlic, and sauté for 1 minute until fragrant.
Whisk in heavy cream and bring to a gentle simmer.
Gradually whisk in parmesan cheese until melted and the sauce thickens.
Season sauce with salt and pepper to taste.
Add the cooked pasta and chicken back into the skillet and toss to coat thoroughly.
Garnish with fresh parsley before serving.