Parmigiano-Reggiano, Grana Padano and Pecorino Romano may be the Three Tenors of the Italian cheese world, but in Sicily's Messina province, the most celebrated grating cheese is ricotta al forno stagionata. Made like most fresh ricotta in this regionwith a blend of cow's, goat's and ewe's milkthis baked variety is dried with salt, formed in a ceramic bowl, blasted in a stone oven three times and aged for 45 days. The result is a dense wheel with an amazing nutty flavor and sweet caramelized richness that's ideal for tomato-based sauces. So rare is this specialty that in the U.S. even the most resourceful cheese mongers can only offer up a lesser substitute, ricotta infornata. But at least one has started selling ricotta al forno: Formaggio Kitchen in Cambridge, Massachusetts ($18 per pound; 888-212-3224).