Does anyone out there have a trick for keeping freshly made pesto from oxidizing and going all army brown in 15 seconds? When storing any leftovers in the fridge, I top the pesto with a thin film of olive oil and this seems to work pretty well, but when I serve it tossed with pasta or spooned on a fresh tomato slice, it goes all funky in a hurry. It almost always stays a vibrant green when I order a dish with it in a restaurant, so I know there must be a trick....anyone? Thanks.
(Oh, and $10 off your order of $50 or more in the Food52 Shop, too.)