In a medium mixing bowl mix sugar, baking powder, and salt, then add potatoes and butter or margarine; mix well. Gradually add whipping cream and milk, stirring until well blended. Stir in lemon rind, juice, vanilla, and nutmeg. Add beaten eggs and mix well.
Pour mixture into pie shells and put in preheated oven. Bake for 55 minutes or until knife inserted in center comes out clean. Best when served cold.
