Make the pie dough and fit into a 9-inch pie dish.
Pre-heat the oven to 350°F.
Melt the butter and stir in the flour, cornmeal, lemon juice, zest, sugar, vanilla extract, sour cream and buttermilk.
Add the egg and stir until mixture is just combined.
Pour into the unbaked pie shell.
Bake the pie on the bottom rack for 45 to 50 minutes, or until center is set, and an inserted toothpick comes out clean. (The top will be slightly golden brown).
Remove the pie from the oven and allow it to cool before adding a topping.
If desired, top with fresh berries and sprinkle confectioners' sugar over the top.