Lightly spray 8 (3½-inch) tartlet pans with cooking spray.
In the work bowl of a food processor, pulse together flour, sugars, and salt until combined.
Add cold butter, pulsing until it resembles coarse crumbs.
With processor running, add 1 tablespoon ice-cold water, pulsing until mixture comes together and a ball of dough forms.
Turn out dough onto a lightly floured surface, and divide in half.
Shape each dough half into a disk, and wrap in plastic wrap.
Refrigerate for at least 30 minutes.
Preheat oven to 375°.
Working with one dough portion at a time, turn out dough onto a lightly floured surface.
Using a rolling pin, roll out dough to a ¼-inch thickness.
Using a tartlet pan as a guide, cut 4 shapes from each dough portion.
Being careful not to stretch dough, place dough pieces on top of prepared pans.
Lightly press dough into bottom of pans, trimming excess as needed.
Using a rolling pin, roll over tops of tartlet pans to trim excess dough.
Using the wide end of a chop-stick, press dough into indentations in sides of pans.
Place tartlet pans on a rimmed baking sheet, and freeze for 15 minutes.
Place a 5-inch square of parchment paper in each tartlet pan, letting ends extend over edges.
Add pie weights.
Bake for 10 minutes.
Carefully remove pie weights and parchment.
Using a fork, prick bottoms of tartlet shells.
Bake until light golden brown, 8 to 10 minutes more.
Let cool completely in pans.
Leave shells in pans and use immediately.