How to Make It
Beat butter with a heavy-duty stand mixer fitted paddle attachment on medium speed until creamy. Gradually add granulated sugar and brown sugar, and beat until blended, about 1 minute. Add eggs, 1 at a time, beating until incorporated after each addition. Beat in vanilla until blended and smooth, about 30 seconds.
Process flour, ginger, baking powder, and salt in a food processor until ginger is very finely chopped and mixture is well blended, 1 to 2 minutes. Gradually add flour mixture to sugar mixture, and beat on low speed just until blended after each addition. Shape dough in 2 (6-inch) disks, and wrap each in plastic wrap. Chill until firm, at least 2 hours or up to 24 hours.
Preheat oven to 350°F. Shape each dough disk into about 18 (1 1/2-inch) balls. Place dough balls 2 inches apart on a parchment paper-lined baking sheet. Flatten each dough ball lightly with the palm of your hand, and, if desired, sprinkle each cookie lightly with sparkling sugar. (Chill remaining dough balls until ready to bake.)
Bake in preheated oven until cookies are lightly browned on bottom, 9 to 11 minutes. Cool on baking sheets 5 minutes; remove to wire racks to cool completely. Repeat procedure with remaining dough balls.