In a large pot of salted boiling water, cook the pasta according to package instructions until al dente. Reserve 1 cup of pasta water, then drain the rest and set aside.
In the same pot, while the pasta is cooking, heat the olive oil over medium heat. Add minced garlic and sauté for 1-2 minutes until fragrant, being careful not to burn it.
Lower the heat, then add the crumbled feta cheese and heavy cream into the pot, stirring until the cheese begins to melt and the mixture becomes creamy.
Add the lemon zest and fresh lemon juice to the sauce, mixing well. If the sauce seems too thick, gradually stir in some reserved pasta water to reach your desired consistency.
Stir in red pepper flakes, and season with salt and black pepper to taste. Allow the sauce to simmer for a couple of minutes.
Add the drained pasta to the sauce, tossing everything together until the pasta is evenly coated.
Serve the pasta hot, sprinkled with fresh basil or parsley and grated Parmesan cheese if desired.