Grandmother's Polish Cheesecake

For Dough: For the dough, combine the flour, salt and baking powder in a bowl. Cut in the butter with a fork.

Beat egg into the sour cream. Stir into the flour mixture then stir in the sugar. Knead the dough until well mixed and smooth.

Roll dough on a floured surface into a rectangle. Line a 13 x 9 x 2 pan with the dough and bring dough part the way up sides.

For Filling: Save mashed potatoes from the night before.

Separate 1 egg and reserve the whites, beat remaining yolk and whole eggs with the sugar for 5 minutes at high speed of a electric mixer. Add the vanilla, beat at high until the mixture is soft.

Press cheese through a sieve. Blend cheese with butter, add the potatoes, baking powder, nutmeg, and salt. Stir in orange peel. Fold into the egg mixture.

Turn into prepare crust in pan. Bake at 350 degrees F for about 45 to 55 minutes or until set. Cool well before cutting.