Grana and parmesan are generic names for hard grating Italian cheeses. In Lombardy we make Grana Padano (a Protected Designation of Origin product), which is similar to the famous Parmigiano Reggiano from the adjoining region of Emilia Romagna β you could substitute that if itβs what you have on hand. Most importantly, always buy a whole piece of Grana and grate it yourself β avoid the pre-grated stuff you can buy in supermarkets.