Grate the Parmesan and Romano cheeses fresh from a wedge. Pre-shredded cheeses often contain cellulose, preventing them from melting smoothly. Adjust sauce thickness with reserved pasta water as needed. Store leftovers in an airtight container in the refrigerator for up to 3 days or freeze for up to 3 months. Reheat gently over low heat with a splash of milk or chicken broth to restore consistency.