Cook pasta in salted water according to package directions. Drain, reserving 1 cup cooking liquid.
Transfer pasta to a large bowl, and mix in reserved cooking liquid, cheese, lemon zest and juice, mint, oil, and red-pepper flakes, if desired. Divide among dishes, garnish with cheese, and serve immediately.
To lend this dish a different aromatic boost, add torn fresh basil in place of the mint.
When this recipe was made on "Mad Hungry", 2 tablespoons fresh lemon juice was used and 1 tablespoon butter was mixed with pasta.