In a mixing bowl, combine your peeled and deveined shrimp with smoked paprika, garlic powder, onion powder, and Cajun seasoning. Mix until shrimp are thoroughly coated. Set aside.

Bring a large pot of salted water to a boil. Add the fettuccine, cooking until al dente, about 8-10 minutes. Drain, reserving some pasta water.

In a skillet over medium-high heat, heat cooking oil and butter. Once hot, add the shrimp, cooking for about 3 minutes on each side. Remove from the skillet and set aside.

Lower heat and add remaining butter to the skillet. Whisk in flour, stirring for 1-2 minutes until it forms a smooth roux.

Gradually pour in chicken broth and heavy cream while whisking. Simmer gently, then add lemon juice, lemon zest, garlic, and Cajun seasoning to taste.

Simmer uncovered for 10 minutes. Mix in Parmesan cheese and parsley and let simmer for another 5 minutes.

Add drained fettuccine to the skillet, tossing gently to coat with the sauce. Add the seared shrimp, folding them into the dish. Adjust sauce consistency with reserved pasta water if needed.

Plate the Cajun Shrimp Alfredo Pasta, garnishing with additional parsley and Cajun seasoning if desired. Serve warm.