Prepare the Chicken:
Slice chicken breasts in half horizontally to create four thin fillets.
In a small bowl, mix smoked paprika, garlic powder, onion powder, salt, oregano, thyme, black pepper, and cayenne. Coat the chicken evenly.
Heat a large skillet over medium-high heat and add olive oil.
Sear chicken for 4-5 minutes per side until blackened and cooked through (internal temp: 165°F).
Transfer to a plate and cover loosely with foil.
Cook the Pasta:
Bring a large pot of salted water to a boil.
Add fettuccine and cook until al dente, according to package instructions.
Reserve 1/2 cup pasta water, then drain and set aside.
Make the Cajun Alfredo Sauce:
In the same skillet, melt 2 tbsp butter over medium-low heat.
Add minced garlic and 1 tbsp reserved blackening seasoning, cooking for 1-2 minutes until fragrant.
Pour in half of the chicken broth, then whisk the remaining broth with cornstarch until smooth. Add to the skillet along with heavy cream.
Simmer for 3-5 minutes, stirring occasionally, until the sauce thickens.
Reduce heat to low, then stir in Parmesan cheese until fully melted and smooth.
Combine & Serve:
Add cooked fettuccine to the sauce, tossing until evenly coated. Add reserved pasta water as needed to loosen the sauce.
Slice rested chicken and arrange over the pasta.
Garnish with fresh parsley and extra Parmesan. Serve immediately!