Place the cashews in a blender or food processor. Start by pulsing the cashews for about 30 seconds. Once the cashews are broken into pieces, start blending continuously. Once the mixture turns thick and chunky, stop the blender frequently and scrape down the sides with a rubber spatula.
At this point, add in the coconut oil. Keep blending until the oils have been released from the cashews and a nut butter forms. It should now have a shiny sheen to it.
Add salt and sugar to taste, if desired.
Transfer to a separate container and serve.
It should take about 10 minutes total, depending on your equipment and the consistency you prefer for the nut butter. I used my Cuisinart stick hand blender with the chopper attachment and it worked well, but I had to take a few breaks to allow the motor to cool down (which was a perfect opportunity to take the below series of the transformation of the cashews into the nut butter).