Step 1

Place potato into a saucepan with enough water to cover and bring to a boil. Reduce heat to medium-low and cook potato until very tender, about 15 minutes. Drain and allow to steam dry for a minute or two.

Step 2

Transfer potato to a large bowl and mash with a fork until smooth.

Step 3

Gradually stir confectioners' sugar into mashed potato a little at a time until the mixture forms a stiff dough. The dough will be runny until all the powdered sugar is used.

Step 4

Place a large square of waxed paper onto a work surface. Roll or press dough into a 12-inch square rectangle on the waxed paper.

Step 5

Spread peanut butter over top of dough, covering it entirely.

Step 6

Pick up one edge of waxed paper and start rolling the dough to make a 12-inch-long log. Wrap log tightly with waxed paper.

Step 7

Refrigerate for 1 hour. Unwrap log and slice candy into cross-sectional pieces about 3/4-inch thick to serve.