1. Bring a large pot of salted water to a boil and cook the fettuccine according to package instructions until al dente. Drain and set aside.
2. In a large skillet, melt the butter over medium heat. Add the garlic and sauté until fragrant, about 1 minute.
3. Add the shrimp to the skillet, seasoning with salt and pepper. Cook until the shrimp are pink and opaque, about 3-4 minutes. Remove the shrimp from the skillet and set aside.
4. Lower the heat and pour in the heavy cream, stirring to combine with the garlic butter. Allow it to simmer gently for 2-3 minutes, until slightly thickened.
5. Stir in the Parmesan cheese until melted and the sauce is creamy. Add the lemon juice and adjust seasoning if needed.
6. Return the cooked shrimp to the skillet along with the pasta. Toss everything together to coat the pasta and shrimp in the sauce.
7. Sprinkle with fresh parsley and, if desired, a pinch of red pepper flakes for a little heat.
8. Serve immediately, garnished with extra Parmesan if desired.

This recipe is as much about intuition as it is about instruction. Trust your senses and taste as you go, a lesson my grandmother instilled in me from a young age.