Start by bringing a large pot of salted water to a boil. Add the fettuccine pasta and cook according to the package instructions until al dente. Once cooked, reserve about 1 cup of the pasta water, then drain the fettuccine in a colander and set aside.
In a large skillet, heat 1 tablespoon of olive oil over medium heat. Add the sliced Andouille sausage and cook for about 3-4 minutes, or until nicely browned.
Once the sausage is cooked, add the shrimp to the skillet. Sprinkle the Cajun seasoning over the shrimp and toss to coat. Cook for about 2-3 minutes, or until the shrimp turns pink and opaque.
Add the diced onion and minced garlic to the skillet. Sauté for an additional 2-3 minutes, until the onions are translucent and fragrant.
Pour in the chicken stock and bring the mixture to a gentle simmer. Allow it to cook for about 2 minutes to reduce slightly. Then, add the heavy cream, stirring well to combine.
Gradually stir in the grated Parmesan cheese, black pepper, and cayenne pepper. Keep stirring until the cheese has melted and the sauce is smooth and creamy.
Add the cooked fettuccine to the skillet, tossing to coat the pasta evenly with the creamy Cajun sauce.
Once everything is combined, remove the skillet from heat. Serve the Cajun Shrimp Fettuccine Alfredo hot, garnished with fresh minced parsley.
