Add flour, sugar and salt in a small mixing bowl and mix thoroughly with a whisk. Transfer flour mixture to a food processor fitted with the dough blade. Add cubed cold butter to the flour mixture, pulse several times until butter is about pea and bean size. Variations in size are okay.
Turn the food processor to “on” position and drizzle cold water over the dough mixture through the water hole, as soon as the dough starts to pull together turn the food processor off. You may need to stop the food processor in between and get a spatula to mix up the flour at the bottom.
Turn the dough out on the counter or cutting board, and shape into a disk. Wrap in plastic and rest in the refrigerator for at least an hour. Make the streusel while waiting.
Take the disk of pie dough out of the fridge and roll into a circle about 2” larger than your pie dish. Use extra flour to keep the dough from sticking to the counter and roller.
Carefully place the dough over the pie dish, lightly press the dough into the bottom and side of the pie dish, let the excess dough hang over the side. Trim all the excess dough leaving just enough to fold under and create a fluted edge.
Cover the pie dish with plastic wrap and keep refrigerated or freeze for 15 - 30 minutes.