Cook the spaghetti until al dente according to the package instructions. Drain the pasta, making sure to reserve 1 cup of the pasta water.
In a large pot over medium heat, melt the butter.
Add the grated garlic, salt, and black pepper to the pot. Stir for about 1 minute, or until the garlic becomes fragrant.
Mix in the lemon juice and lemon zest, followed by the cooked spaghetti.
Stir in ¾ cup of the reserved pasta water and the freshly grated parmesan cheese. Toss everything together to coat the pasta evenly.
If the pasta seems dry, add more reserved pasta water as needed.
Serve the pasta with fresh parsley and additional parmesan cheese on top, if desired.
