Line a pie pan with the dough. Prick the dough with a fork and press a piece of aluminum foil snugly into the pan, covering the dough. Bake 6 minutes. Remove the foil and bake 6 minutes more, until the edges of the crust turn palel brown.
Remove the pan from the oven and cool.
Mix together the sugar and flour. Beat in the eggs, then the melted butter, buttermilk, vanilla extract, lemon juice, and zest.
Pour the filling into the cooled pie shell and bake at 425 degrees 10 minutes. Sprinkle top with nutmeg. Lower the oven temperature to 350 degrees and bake 30 minutes more or until a knife inserted into the pie comes out clean.
Remove the pie from the oven and cool. The center will deflate as the pie cools. Leftover pie can be refrigerated.