Cook the fettuccine pasta according to package instructions until al dente. Drain and set aside, reserving 1/2 cup of the pasta water.
In a large skillet, heat the olive oil over medium heat. Add the chopped onion and sauté until translucent, about 3-4 minutes.
Add the minced garlic and cook for an additional 1 minute, stirring frequently to prevent burning.
Pour in the heavy cream and bring to a gentle simmer. Stir in the lobster meat, Parmesan cheese, and red pepper flakes (if using). Mix well and let it cook for 2-3 minutes until the sauce thickens slightly.
Add the cooked fettuccine to the skillet, tossing to coat the pasta in the creamy sauce. If the sauce is too thick, add some reserved pasta water, a little at a time, until the desired consistency is reached.
Season with salt and pepper to taste.
Serve immediately, garnished with chopped parsley.