Put the flour, sugar (if using) and salt in a large food processor fitted with the metal blade and pulse a few times to combine.
Add the cubed butter and quick pulse 3-5 times until butter is broken up and the smallest pieces the size of large peas. It's okay if you still have some larger pieces.
Begin to gradually add ⅓ water through the top, and then while still pouring, run the food processor until all the water has been added and mixture begins to come together (mixer will actually begin to make a different sound), but stop before it forms a complete ball. It will look a little crumbly but actually holds together when you pink it. (This whole step should take less than 10 seconds total!)
Turn dough out onto a clean surface and form into 2 equal disks with your hands. If the dough won't come together as you work it, add more water 1 tablespoon at a time, sprinkling it over the dough.
Once formed into disks, cover in plastic wrap and chill in the fridge for at least 1-2 hours and up to 3-5 days. Pie crust also freezes very well, up to 2 months. Double wrap in plastic wrap to prevent freezer burn, and thaw overnight in the fridge before using.
Use pie crust as desired with your favorite pie recipes.