Begin with a large to medium pot and fill with water. Make sure your potatoes are covered with water and boil with skin on. (take about an hour or so to cook)They are done once you pierce with a fork all the way through with no difficulty. Remove and let cool in cold water for about 20 minutes.
Remove skin (should just peel right off.).
In a large mixing bowl whisk your potatoes until creamy. Add your egg, sugar, cinnamon, nutmeg and vanilla. After mixed well add your melted butter and fill your pie crusts.
Cook for about an hour or until firm (until filling is firm). Let cool and enjoy.