Cooking this dish is a delightful process. Follow these steps for a perfect result:

1. Start by bringing a large pot of salted water to a boil. Cook the fettuccine according to the package instructions until al dente. Drain and set aside.
2. In a large skillet over medium heat, add olive oil. Once hot, add the minced garlic and sauté until fragrant, about 1 minute.
3. Add the mixed seafood to the skillet. Cook until the shrimp turns pink and the scallops are opaque, about 4-5 minutes.
4. Pour in the white wine, stirring to deglaze the pan. Let it simmer for 2 minutes to allow the alcohol to evaporate.
5. Reduce the heat to low and stir in the heavy cream. Allow it to simmer gently for 3-4 minutes until it begins to thicken.
6. Add the Parmesan cheese, stirring continuously until the cheese melts and the sauce becomes smooth and creamy.
7. Season with salt, pepper, and lemon zest. Taste and adjust seasoning as needed.
8. Add the cooked pasta to the skillet, tossing gently to coat the pasta with the creamy sauce.
9. Garnish with chopped parsley before serving. Enjoy the dish warm, perhaps with a slice of crusty bread to mop up any remaining sauce.

Remember, cooking is as much about intuition as it is about following instructions. Feel free to adjust spices and flavors to match your personal preference, just as my grandmother did.