Parmesan cheese is a hard, dry granular cheese with a pale golden rind and straw-colored interior. Made from cow's milk, it has a sharp, pungent flavor. Although Parmesan cheese is made in many countries, the most highly prized is Parmigiano-Reggiano from Parma, Italy. This cheese is aged two to four years, had supreme flavor and a characteristic granular texture. It is typically more expensive than domestic varieties, but is heightened flavor means that less is needed. Parmiagiano-Reggiano is available at Italian markets and in the deli departments of large supermarkets.
Parmesan cheese is primarily used grated, though restaurants sometimes "shave" it for a slightly different effect. You can purchase the cheese pre-grated in canisters. For freshest flavor, buy it in chunk form and grate it as needed, using a food processor or the fineholed side of a hand grater.