Add the raw cashews to a high-powered blender, dry blender pitcher, or food processor. Make sure there is no water or oil inside.

Blend the cashews on high speed until they become a fine powder. Stop and scrape down the sides as needed. Be careful not to overblend or the nuts will turn into cashew butter.

Add the sugar if desired and blend again to further grind the powder. The sugar granules help break down the cashews.

Sift the cashew powder through a fine mesh sieve. Return any large bits back to the blender to process again until powdered.

Store the cashew powder in an airtight container in the refrigerator for a few months or the freezer for up to a year.