Lightly spoon flour into a dry measuring cup, and level with a knife. Combine flour and the next 4 ingredients (through ground ginger); stir with a whisk. Combine sugar and butter in a large bowl, and beat with a mixer at medium speed until light and fluffy (about 5 minutes). Scrape sides of the bowl occasionally. Add egg; beat well. Beat in grated lemon rind. Add flour mixture to butter mixture, and beat at medium-low speed just until blended.
Spoon about 1 1/2 teaspoons batter 2 inches apart onto 2 parchment-lined baking sheets. Bake at 350°F for 12 minutes or until lightly browned and almost firm. Remove from oven. Cool on pans for 2 minutes or until firm. Remove from pans. Cool completely on a wire rack.