Put the peanuts and the salt in your blender or food processor.
Process the peanuts into fine crumbs. Stop and scrape down the sides of the blender to clear off any peanuts. This will help achieve consistent smoothness.
Continue blending—stopping every 30 seconds to scrape down the sides and allow the appliance's motor to cool down—until you get a smooth, consistent texture. The transformation typically takes 8-10 minutes, including breaks.
Enjoy your peanut butter straight from the blender, or chill it for an hour or so for a firmer texture.