Preheat your oven to 325° F. Press your gluten free pie crust into the pie dish or get the one ready you bough. If it's raw dough, dust lightly with gluten free flour. Make sure it's chilled.
In a medium mixing bowl, beat the eggs slightly.
Whisk in the sugar and flour, then mix in the melted butter, buttermilk and vanilla, and whisk until well combined.
Pour the buttermilk batter into your prepared gluten free pie shell. Sprinkle a little more gluten free flour on top of your buttermilk batter.
Bake the pie for about an hour, or until the custard is set.
Serve your gluten free buttermilk pie warm or refrigerate and eat cold the next day.