Combine the flour, powdered sugar and 1 stick of butter in a food processor and pulse until mixture resembles coarse sand. Add the egg yolk and 1 teaspoon of water and continue to pulse until dough just begins to come together.
Turn dough out onto a lightly floured surface and knead until smooth. Shape into a disc, cover with plastic wrap and refrigerate for 1 hour.
Spray a rectangular tart pan, approximately 13” x 4” x 1”. Roll out the dough large enough to line the pan. Ease the dough into the pan and press gently to form; trim the edges. Cover and refrigerate for 10 minutes.
Preheat oven to 350°F. Line the tart shell with parchment paper and fill halfway with dried beans or rice. Bake for 10 minutes. Remove the beans or rice and the parchment paper and bake for another 5 minutes until lightly golden. Remove from oven and set aside to cool.
