COOKS AROUND THE WORLD (myself included) have, for years, believed that you do not cook with extra-virgin olive oil: You cook with a lesser olive oil and finish with the more expensive extra-virgin. But I’ve been rethinking the issue. Since extra-virgin olive oil simply means oil pressed naturally from olives with no additives, I suggest that when you’re cooking with olive oil, use only extra-virgin. I can’t be sure that anything other than extra-virgin is indeed even olive oil. Bottles marked just “olive oil” could be blends of lower-grade oils, and their country of origin is murky at best. California olive oils seem to be well-regulated. So when I call for olive oil in this book, I always mean extra-virgin olive oil, marked with its place of origin. Find one that you like and can afford (sure, there are the rarified extra-virgins that, like wine, you’d rather drink than cook with, but I’m not talking about those) and use it.