Cook fettuccine in a large pot of salted boiling water until al dente (1 to 2 minutes less than package instructions). Reserve 1/2 cup of starchy pasta water, then drain and set aside.

Pat chicken cutlets bone-dry with paper towels. Season generously on both sides with Cajun seasoning, garlic powder, and kosher salt.

Heat olive oil in a large 12-inch heavy skillet over medium-high heat. Add chicken cutlets in a single layer and sear undisturbed for 4 to 5 minutes per side until blackened, deeply golden, and cooked through (165°F / 74°C). Transfer to a cutting board to rest.

Reduce skillet heat to medium. Melt butter in the skillet drippings, add minced garlic and halved cherry tomatoes, and sauté for 60 seconds until fragrant and blistered.

Pour in low-sodium chicken broth, scraping up all flavorful blackened Cajun fond bits from the skillet bottom. Simmer for 1 to 2 minutes until reduced slightly.

Lower heat to medium-low. Pour in heavy cream and 1 teaspoon of additional Cajun seasoning. Bring to a gentle simmer, then whisk in freshly grated parmesan cheese until completely smooth and velvety.

Toss the drained fettuccine directly into the simmering Cajun alfredo sauce, stirring gently for 1 to 2 minutes until every ribbon is richly coated (add a splash of reserved pasta water if needed to loosen).

Slice the rested Cajun chicken into strips and arrange over the creamy pasta. Garnish with chopped fresh parsley, extra parmesan shavings, and freshly cracked black pepper. Serve immediately.