Preheat oven to 350 degrees. Arrange pie crusts in 2 9 inch pie plates.
Mix together the sugar, flour, and salt. Beat in the eggs, butter, buttermilk, and vanilla until well combined.
Pour into the pie crusts. Bake for 1 hour or until no longer jiggly - check them after about 45 minutes. If the tops are getting too brown (mine were), cover them loosely with foil.
Let cool at least one hour before serving. Best served cold.