Beat the potatoes with the vanilla, milk and salt for 2 minutes using an electric mixer.

Mix in a cup of powdered sugar at a time, until you have a dough that’s a bit thicker than cookie dough.

If the mixture is too loose, you can add more powdered sugar, a tablespoon at a time.

Shape the dough into a ball and then dust it with powdered sugar.

Roll it out to make a 12x10-inch, 1/8-inch thick rectangle on a sheet of parchment paper.

Sprinkle powdered sugar on top then put another sheet of parchment paper on top.

Flip the whole thing over and peel off the parchment paper on top (that started off on the bottom).

Spread the peanut butter over the dough and then roll from long side to long side to make a jelly roll shape.

Wrap in parchment or wax paper or in plastic wrap and freeze for an hour to set.

Cut into ¼-inch pieces to serve.