Roll out the potato candy to a 12-by-10-inch rectangle (about ¼-inch thick), dusting the top with powdered sugar if it becomes sticky. Spread the peanut butter in an even layer over the potato candy.

We live at the edge of Pennsylvania Dutch Country, where there are lots of small farms. Country markets are plentiful here, so potatoes are a staple. I use them up in this delicious old-fashioned ...