In a large pot or deep skillet, combine the pasta, broth, olive oil, minced garlic, and lemon zest.
Bring the mixture to a boil over high heat, then reduce to medium-low and simmer.
Cook for 8-10 minutes, stirring frequently to prevent the pasta from sticking.
As the pasta cooks, the liquid will reduce and form a creamy sauce.
Once the pasta is al dente and most of the liquid has been absorbed, remove from heat.
Stir in the lemon juice, Parmesan cheese, and heavy cream until well combined.
Add chopped parsley, salt, and pepper to taste.
Let the pasta rest for 2-3 minutes to allow the sauce to thicken.
Serve hot, garnished with extra Parmesan and red pepper flakes if desired.