Boil the pasta in salted water until less than al dente.
Reserve a cup of water for the pasta.
In a pan over low heat with oil, add the chili flakes and chopped garlic, sauté gently.
Add the lemon juice along with the zest, cook for a few minutes.
Once the pasta is cooked almost al dente, drain it and add it directly into the pan.
Pour in half a cup of the pasta water, season with salt and pepper.
Stir and cook until all the liquid has evaporated.
Add the pieces of butter, cooking until they are fully incorporated into the other ingredients.
Sprinkle the chopped parsley, add the grated hard cheese, mix well, and serve immediately.
Enjoy!
