Add the flour, sugar and salt to a food processor and pulse just until combined. In a small bowl, whisk mix together the egg, vinegar and water. Add the cold butter pieces into the food processor and pulse until small coarse crumbs remain. Sprinkle the water/egg mixture over the flour and pulse again until the dough comes together.
Remove the dough with your hands and wrap it in plastic wrap. This dough makes enough for 3 pie crusts, so you can either separate it into 3 sections now, or separate it after it’s refrigerated. Refrigerate the dough for 30 minutes.
After 30 minutes, preheat the oven to 375 degrees F. Roll the pie crust out into a 12-inch circle (if you’re using a 9-inch pie plate). Fold it in half to pick it up and gently place it in the plate, unfolding as you go and trimming any excess off of the edges – you can also use a fork (or another decorative idea!) to press the edges down. At this point, I covered my crust with parchment paper, filled it with dry beans (or pie weights) and bake for 10 minutes. Once finished, tap any bubbles on the bottom with a fork.