Whisk together the flour, sugar and salt. In a food processor, or using a pastry cutter, add butter to the flour mixture and pulse until the mixture is coarse and crumbly (about 20 pulses). Add in the egg and vanilla extract and pulse for another 20 seconds, until the dough starts to clump together, but not so long that the dough becomes a ball.
Turn the dough out on a lightly floured surface and roll into a ball. Wrap with plastic wrap and put into the fridge for at least an hour.
After an hour, take the dough out of the fridge and put it onto a lightly floured surface. Roll the dough into an 11 inch circle, then place the dough into a 9 inch tart pan. Cover the pan with plastic wrap, then place the dough into the freezer for 30 minutes.
Preheat the over to 375°F. Take the dough out of the freezer, and trim the edges of the pastry to slighly longer than the tart pan. Press aluminum foil on top of the crust, covering the edges to prevent burning. On top of the foil fill the crust with pie weights or dried beans.
Bake the crust for 20 minutes. Remove the pie weights and foil, place the crust back into the oven and cook for another 5 minutes until the crust is golden. Set aside to cool.