Heat oven to 350℉.
Combine flour, sugar, and baking powder in the bowl of a food processor fitted with a dough blade.
Pulse to combine.
Add butter, a little at a time, pulsing until combined.
Add egg and vanilla.
Pulse until it forms a smooth dough.
Turn dough out onto a sheet of parchment paper.
Form into a ball.
Flatten slightly.
Cover with another sheet of parchment paper.
Roll into a circle that it ¼ inch thick.
Carefully fit dough into 9 inch tart pan, making sure to press out air bubbles.
Trim edges.
Place a piece of parchment paper on top of the tart dough.
Fill with pie weights.
Bake for 20 minutes.
Remove from oven.
Carefully remove pie weights.
Cover edges of dough.
Return to oven.
Bake for 15 minutes, or until crust is light golden brown.