Begin by cooking the fettuccine pasta according to package instructions in a large pot of salted boiling water. Drain and set aside.
In a large skillet, heat 1 tablespoon of olive oil over medium-high heat.
Add the sliced steak to the skillet and season with half of the Cajun seasoning. Cook for about 3-4 minutes, or until browned and cooked to your desired doneness. Remove from the skillet and set aside.
In the same skillet, add another tablespoon of olive oil. Add the shrimp, the remaining Cajun seasoning, salt, and pepper. Cook for about 2-3 minutes, or until shrimp are pink and cooked through. Remove from the skillet and set aside with the steak.
In the skillet, add the minced garlic and sauté for about 30 seconds until fragrant. Then pour in the heavy cream, stirring to combine. Bring to a gentle simmer.
Gradually add the grated Parmesan cheese to the cream, stirring continuously until the cheese has melted and the sauce is smooth.
Combine the cooked pasta, shrimp, and steak into the skillet with the Alfredo sauce. Toss gently until everything is well coated with the sauce.
Serve the pasta hot, garnished with chopped parsley.