Place the peanuts in a food processor, and process for 1 minute. Use a spatula to loosen mixture from the sides of the bowl if the mixture is sticking. Then continue to process until completely smooth, about 2-3 more minutes.
Transfer to an airtight container, cover and refrigerate until use. Peanut butter should keep for between 3-4 weeks in the refrigerator. Stir each time before using.