Nana Clara swore this was her 3 ingredient miracle when money was tight. I never believed her until I watched an entire platter disappear

Spread the peanut butter: Gently spread the 1/2 cup creamy peanut butter evenly over the rolled dough, leaving about a 1/2-inch border around the edges so it doesn’t squeeze out when you roll. An offset spatula or the back of a spoon works well for this.
Roll into a log: Starting from one of the long sides, use the parchment or your hands to carefully roll the dough into a tight log, just like you would roll cinnamon rolls. Take your time, lifting and rolling so the dough doesn’t crack. If it does crack a bit, just pinch and smooth it back together—no one will notice once it’s sliced.
Wrap and chill: Once you have a log, dust your hands with a little powdered sugar and gently smooth the outside. Wrap the log snugly in the parchment or plastic wrap, twisting the ends like a candy wrapper. Place it in the refrigerator for at least 1–2 hours, or until very firm. This helps the pinwheels hold their shape when you slice them.
Slice the candy: When the log is firm, unwrap it and place it on a cutting board. Using a sharp knife, slice the log into 1/2-inch thick pieces. Wipe the knife clean with a damp cloth as needed to keep the slices neat. You’ll see the white candy with a brown peanut butter swirl in the center.
Arrange for serving: Set the slices cut-side up in a glass rectangular serving dish so the swirl shows, just like those old family picnic platters. If the candy softens while you’re arranging it, you can pop the dish back into the fridge for 10–15 minutes to firm up again before serving.
Store: Keep any leftovers covered in the refrigerator for up to 5 days. For a firmer, less sticky texture at a picnic, serve them straight from the fridge and don’t leave them sitting out in the sun. They can also be frozen in a single layer, then transferred to a container with parchment between layers for up to 1 month.
Variations & Tips
For picky eaters who aren’t into peanut butter, you can spread a thin layer of smooth hazelnut spread, cookie butter, or even a favorite jam instead—just keep the layer thin so the candy still rolls well. If you have peanut allergies in the family, use sunflower seed butter or another nut-free spread; the method stays the same. For a little extra flair without adding more ingredients, lightly dust the finished slices with a bit of powdered sugar right before serving so they look extra snowy in the glass dish. You can also roll the dough slightly thinner and make two smaller logs instead of one large one; they chill faster and make smaller, bite-size pieces for younger kids. Food safety tips: Make sure the mashed potatoes are fully cooked and cooled before you start, and don’t use potatoes that have been sitting out at room temperature for more than 2 hours—bacteria can grow quickly in cooked starchy foods. If you’re using leftover mashed potatoes, they should have been stored in the refrigerator and used within 3–4 days. Because this candy is quite sweet and made with a fresh ingredient (potato), always store it covered in the refrigerator and avoid leaving it out at room temperature for longer than 2 hours, especially at warm-weather picnics. Use clean utensils and a clean work surface when handling the dough, and wash hands well before and after shaping and slicing.