Combine flour, confectioners' sugar, cornstarch, salt, and butter into a large food processor. Pulse for about 30 seconds or until butter becomes pea sized clumps. Scrape the bowl as needed.
Beat egg and combine with vanilla paste. Then add into the butter/flour mixture. Pulse until just combined and a dough ball begins to form.
Scrape the edges of the bowl and turn mixture onto a clean surface. Mix residual flour into the dough. Then form into a flat disc and wrap with plastic wrap. Refrigerate at least 30 minutes before use.
Before baking, thaw for at least 10-15 minutes to allow dough to be pliable enough to roll.
Preheat oven to 350 degrees F.
Sprinkle a clean surface with flour. Roll dough until it is about 1/4 inch thick. Place onto your tart shell, pushing the dough onto the edges of the pan. Remove excess dough. Refrigerate dough for another 15 minutes to allow it to hold shape. Then line the top of the tart shell with parchment paper and fill with beans.
Bake tart shell at 350 degrees 15-20 minutes or until golden brown.
Remove parchment paper and beans from tart shell and check for doneness. The bottom of the tart shell should be golden brown and crisp. If it is still soft, turn oven to 300 degrees, and bake for another 5-10 minutes or until the bottom is golden brown and crisp.
When tart shell is golden brown and crisp, remove from the oven and allow to cool completely, at least 30 minutes.