parmesan.. or Parmiggiano-Reggiano as the italians call it. Yes, I've bitched about using the real thing and NOT the sawdust that comes in a green can.. In my experience, if a product promises it doesn't have any fillers.. it has.. so get a block or wedge of the reall stuff and grate your own you will definitely not regret it. Unless, of course you grate your knuckles.. well, the you've got more issues than the sawdust you sprinkle on your pasta.
A word of caution to all y'all vegans.. this cheese is made with rennet.. yes, baby cow stomach lining... it's used for a lot of cheeses and well, I don't mind, but if you're true to your cause you should.
Surprisingly, it's not a D. O. C. (Denominazione Di Origine Controllatta) like wines, but it is, after all a regional denomination indicating some traditional method of preparation. That wiki article I linked to at the beginning of this post mentions that aside from rennet, this cheese is traditionally made with grass-fed cows milk, I hear that's a good thing.. and, yes, it is.
The wiki article also mentions traditional uses such as sprinkling over pasta (no surprise there), making risotto or eating on it's own with a bit of balsamic vinegar, again, no surprise really, it's made in regions near Modena, where the good balsamic is traditionally made. As a rule of thumb, traditional combinations are traditional because gawd-damn! they taste good, Port and Stilton anyone?