In a large mixing bowl, combine the flour, sugar, salt, and butter. Mix until the mixture is crumbly.
In a medium mixing bowl, combine the egg, egg yolk, vanilla extract, and lemon zest, and lightly beat with a fork.
Add the egg mixture to the flour mixture and beat with a mixer on low speed for about 2 minutes, or until a dough forms.
Turn the dough out onto a lightly floured work surface.
Dust your hands with flour and knead the dough for 1 minute.
Wrap the dough in plastic wrap and chill for at least 1 hour (or up to 4 days). If you chill the dough for longer than 1 hour, let it warm slightly before rolling it out.
Preheat the oven to 400°F.
Roll the dough out on a lightly floured surface to 1/4 inch and transfer to a 9-inch tart dish with removable bottom. Trim off any excess dough.
Bake for 25 minutes. Let cool.