Pistachio Pesto

Let me tell you about Pistachio Pesto, and how to treat it with respect.

This is a raw sauce. Nobody cooks it, and that's the whole point. Pistachios get crushed with oil, cheese and herbs, and nothing here ever sees a flame. Leave it standing too long and the oil will rise to the top; that's normal, just stir it back in before you use it.

Choose it by color first. It should be a real green, not a dull olive-brown. Smell it too: fresh Pistachio Pesto smells nutty and bright, with the herbs still alive in it, not flat or heavy.

Some people say pesto is pesto: you can treat pistachio pesto the same as basil pesto, heating it in the pan and letting it simmer with the pasta. No! Put raw pesto over heat and you'll smell the difference before you see it — the bright, nutty smell flattens out, and the green turns dull and tired. That's the sauce telling you it's ruined. Stir it into the pasta off the heat, right at the end, and leave it alone. Toss, don't cook, and the pesto will coat every strand the way it's supposed to.