1
Cut the peeled and cooked potato into eights and place in a stand mixer. Beat until mashed, then blend in vanilla extract. (This can be done by hand using a fork or potato masher if you don’t have a mixer.)
2
Mix in the powdered sugar in batches until thick and well-blended.
3
Form candy into two equal balls and wrap in cling wrap. Refrigerate for an hour to firm up.
4
Spread waxed paper on your counter or table and sprinkle with powdered sugar. Roll the candy, one ball at a time, to form an 8-inch square on the waxed paper. Spread each square with peanut butter, covering the entire surface.
5
Roll the candy into a tight spiral like a jelly roll. Wrap each roll in waxed paper and refrigerate for 2 hours, or until firm enough to cut.
6
Slice the logs into ½ inch slices and serve. To keep the slices fairly round, rotate the log as you cut it so the bottom doesn't get too squished. Store Potato Pinwheels in the refrigerator in an airtight container.