If you are not using a high-speed blender, quick-soak your cashews by placing them in a small bowl, and covering them with boiling hot water. Allow to sit for 10 minutes, then drain, and discard the soaking liquid. (This will give you the smoothest texture.)

Throw the drained cashews into your blender with the rest of the ingredients, and blast on high for 30 to 60 seconds, until smooth and creamy. You should have about 1 cup of mayo.

Transfer the mixture to a sealed container. It will keep in the fridge for about 5 days.