- 1 small potato, peeled and cubed
- 1 (16 ounce) package confectioners' sugar
- 1 tablespoon milk, or more as needed
- green food coloring (optional)
- 1/3 cup peanut butter
- Place potato cubes in a small sauce pan and cover with salted water. Bring to a boil, then reduce heat to medium-low and simmer until tender, about 15 minutes. Drain and cool.
- Mash potato in a large bowl until smooth.
- Stir 1 cup confectioners' sugar into mashed potato; mix well. Gradually stir remaining confectioners' sugar and milk to form a firm dough. Incorporate green food coloring at this point if using.
- Sprinkle work surface with confectioners' sugar, and roll dough into an 8×12-inch rectangle about 1/2 inch thick.
- Spread peanut butter evenly onto the dough.
- Tightly roll dough into a log, jelly roll-style, beginning at the wide end.
- Wrap log in plastic wrap and chill in refrigerator until the candy sets up, about 1 hour. Cut into 1/4-inch slices.