Lightly spray 12 (3 ½-inch) tartlet pans* with baking spray with flour, and place on rimmed baking sheets.
In the work bowl of a food processor, pulse together flour, sugars, and salt until combined. Add cold butter all at once, pulsing until pea-size pieces of butter remain. Add 2 tablespoons ice-cold water, and pulse until mixture comes together and forms a ball.
Divide dough into 2 portions. Wrap each portion tightly in plastic wrap, and refrigerate until dough is very firm but can be rolled out, at least 30 minutes.
Working with one dough portion at a time, unwrap and place dough on a lightly floured surface. Using a rolling pin, roll out dough to a ¼-inch thickness. Using a 4 ½-inch round cutter, cut 6 rounds from each dough portion, rerolling scraps once. Being careful not to stretch out dough, center a dough round on top of each prepared tartlet pan. Lightly press dough rounds into bottoms of tartlet pans, and stand dough up against sides of pans. Using a rolling pin, roll over tops of tartlet pans to trim excess dough. Using the large end of a chopstick, press dough into indentations in sides of tartlet pans. Freeze for 15 minutes.
Preheat oven to 375°. Spray a large sheet of foil with cooking spray. Cut prepared foil into 12 (3-inch) squares. Place a square, spray side down, into center of each tartlet shell. Place pie weights or dried beans on top of each foil square.
Bake tartlet shells for 10 minutes. Carefully remove weights and foil. Using a fork, prick bottoms of tartlet shells. Bake until light golden brown, 10 to 15 minutes more. Let cool completely before carefully removing tartlets from pans.
Notes
*We used Gobel 3 1⁄2-inch nonstick tartlet pans. Measure diameter of pans across the bottom.
Recipe by TeaTime Magazine at https://teatimemagazine.com/fruit-tartlets-with-lemon-tarragon-syrup/