Toast the pine nuts for fuller flavor – but if you’re rushed, you can skip that step. If pine nuts are hard to find, you could use almonds, walnuts, even peeled sunflower seeds.
Put the pine nuts, garlic cloves, and salt in the bowl of a food processor. Whiz to chop finely and combine. Add the basil leaves, and whiz again.
With the motor running, slowly pour the olive oil through the feed tube, and process until the pesto is thoroughly pureed. Add the cheeses, and puree about a minute more.
Serve, or store with a thin film of olive oil on top
TO FREEZE PESTO
For larger amounts, ½ cup or more: transfer pesto to a sealable container, and cover the surface with a very thin layer of olive oil. Tightly seal the container, and put in the freezer. That layer of olive oil will minimize browning on the surface of the pesto as it freezes.These larger quantities of pesto are perfect for a whole-meal recipe.
For small amounts: put spoonfuls of pesto into ice cube trays, and freeze until solid. Once the cubes are solid, transfer them to a zip top bag. Pesto cubes are excellent for a hit of flavor. Incorporate a cube into a soup or stew, or defrost to spread a bit on a sandwich.
NOTE: if you don’t have pine nuts, you can use toasted raw almonds or walnuts, or even sunflower seeds. You can make a milder pesto with half spinach. This is flexible: adjust the ingredients and proportions to fit your taste and what’s on hand.