Right now I am going through a phase in where I am over Parmesan cheese and more into Pecorino Romano cheese. Romano cheeses, in general, are sharper. Pecorino is made from sheep's milk and has more of a salty & tangy taste. I usually buy a big block of it at Costco's and use it in pasta, salads and pesto. I am eager to try the Caprino Romano, which is made out of goat's milk, but have not found it in the local stores yet. If anyone knows where I can get this without having to order it online, please email me.
Anyhoo- back to the pesto. This time I substituted Parmesan for Pecorino and pine nuts for pecans. We have the motherload of pecans in the freezer from my in-laws, so why buy pine nuts when I can use pecans? Turns out that I like the taste of the pecans much better than the pine nuts. The pecans gave it an earthier taste while the Pecorino brought a saltier flavor (I did not add salt). I also added more garlic cloves (3) and used less olive oil.