Preheat oven to 350. Have a 9 inch pie shell unbaked set aside in your pie plate. In a large mixing bowl, combine sugar, cinnamon, nutmeg, cornstarch, buttermilk, butter, vanilla, and eggs. Blend well.
Pour the filling into your 9 inch unbaked pie shell. Bake in a 350 oven for 40-60 minutes, or until center sets and isn't runny. It should be golden brown.
Remove from oven and let cool completely. Serve with whipped cream it desired.