Add flour, sugar, and salt into a food processor
and blend for a few seconds, then add the cold butter a little at a time. Continue processing until the mixture is crumbly, a couple of minutes. With the food processor still running, add water and vinegar just until well combined. Turn the dough into your buttered pie plate and press it evenly over the bottom and up the sides. Poke it all over with a fork to prevent air bubbles. Bake until lightly golden, about 25-30 minutes. Remove from the oven and lower the temp to 375*.