In the work bowl of a food processor, pulse together flour, brown sugar, and salt until combined. Add cold butter, and process until mixture starts to clump together, about 30 seconds. Pulse until large clumps form and mixture sticks together when pinched, 5 to 6 pulses.
Turn out dough onto a clean work surface, and knead 2 to 3 times to bring together. Press into a disk. Place dough between 2 pieces of parchment paper, and roll to ⅛-inch thickness. Place on a baking sheet, and freeze until firm, 20 to 30 minutes.
Using a 1¾-inch round cutter, cut dough. Reroll scraps between parchment, and refreeze before cutting more disks, about 10 minutes. Freeze disks on a baking sheet or in a resealable plastic bag until ready to use.
Recipe by Bake from Scratch at https://bakefromscratch.com/july-pate-choux-two-ways/