1. Bring a large pot of salted water to a boil. Add fettuccine and cook until al dente; drain and set aside.

2. In a bowl, combine shrimp with salt, pepper, and Cajun seasoning.

3. Heat olive oil in a skillet over medium-high heat. Sauté shrimp for 5-7 minutes until pink and opaque. Remove and set aside.

4. Add 2-3 tablespoons of water and slices of butter to a pan. Simmer to create a poaching liquid, then add lobster tails and poach until cooked. Remove meat and cut into bite-sized pieces.

5. In the skillet, lower heat and add grated garlic; sauté until fragrant. Add heavy cream and bring to a gentle simmer. Stir in Parmesan cheese, herb butter, and parsley until melted and combined.

6. Return shrimp and lobster to the sauce. Add fettuccine, tossing to coat evenly.

7. Serve hot, garnished with extra parsley if desired.