Place the peanuts and oil in the bowl of a food processor and and process for 2 to 3 minutes. That may seem like a long time but it takes that long to get creamy. Stop it every 45 seconds and scrap down the sides.
I have made it a few ways. The longer you keep it in the blender, the smoother it will become. I like mine a little crunchy so I didn't process it as long.
Store the peanut butter in a glass jar or airtight container in the refrigerator for up to 1 month. I stir mine with a knife a few times before each use.