In a large saucepan, cook potatoes in enough boiling water to cover for 20 to 25 minutes or until very tender. Drain; cool slightly. Remove skins.
Meanwhile, prepare Pastry for Single-Crust Pie. Line pastry with a double thickness of foil. Bake in a 450 degree F oven for 8 minutes. Remove foil. Reduce the oven temperature to 375 degrees F.
In a large bowl, beat potatoes with an electric mixer until smooth. Beat in eggs, sugar, butter, nutmeg, cinnamon, vanilla, baking powder, and salt. Stir in evaporated milk. Pour into crust. Cover edge with foil.
Bake in the 375 degree F oven for 20 minutes. Remove foil and bake for 25 to 30 minutes more or until a knife inserted near center comes out clean. Makes 8 servings.
In a large bowl, stir together flour and salt. Cut in shortening until pieces are size of small peas. Sprinkle with 1 tablespoon of cold water; toss with a fork. Push to side. Repeat moistening dough, using 1 tablespoon cold water at a time, until all the dough is moistened (4 to 5 tablespoons cold water total). Form dough into a ball. On a lightly floured surface, use your hands to slightly flatten dough. Roll dough from center to edge into a circle about 12 inches in diameter. To transfer pastry, wrap it around the rolling pin. Unroll pastry into a 9-inch pie plate. Ease pastry into pie plate, being careful not to stretch pastry. Trim pastry to 1/2 inch beyond edge of pie plate. Fold under extra pastry. Crimp edge high as desired.