Remove potatoes from water and mash or whip them thoroughly with an electric mixer or hand masher and strong bicep. Pour mixture into a 9-inch pie shell. Bake in a preheated 400 degree oven for 40 minutes, or until a knife inserted into the center of the pie comes out clean. Let cool 15-20 minutes before serving. Serve plain or with whipped topping.
Pie is very much like pumpkin pie only sweeter, lighter, and a little smoother in texture.
Left over mixture that won't fit into the pie shell can be baked in a lightly buttered small pan or dish as a custard.