One-half cup of leftover mashed potatoes (not instant)
 1 teaspoon vanilla extract
 28 ounces powdered sugar (1.75 sixteen-ounce boxes)
 Smooth peanut butter
In a mixing bowl, combine the leftover mashed potatoes, the vanilla and one cup of  powdered sugar. Set the remaining powdered sugar (about 20
ounces) aside.  Stir until the sugar is dissolved and the mixture becomes a thin syrup. Continue  adding powdered sugar into the mix, while stirring thoroughly. As the  remaining sugar  is added, the mixture will become very stiff and difficult to stir.  Remove mixture from bowl and place on a sheet of  waxed paper that is  coated with powdered sugar. Dust a rolling pin with  powdered sugar and roll out the mixture like  a pizza crust (about 18 inches in diameter).  Using a spatula, spread a generous amount of peanut butter on the mashed potato candy  and curl it up tightly, like a jellyroll.  Wrap candy in waxed paper, and  refrigerate  for three or four hours. Cut into half-inch slices and serve.