How to Make It
Sift flour, spices, and baking soda into a medium bowl. With a hand mixer or standing mixer on medium speed, cream butter in a separate bowl until whipped, about 1 minute. Add brown sugar, beating until fluffy, about 2 more minutes. Beat in molasses, egg yolk, orange rind, fresh ginger, and vanilla on medium-low speed. Add flour mixture, and beat until just blended. Gather dough into a ball; divide and flatten into 2 disks. Wrap each in plastic wrap, and chill until firm, about 4 hours.
Preheat oven to 350˚F.
Line 2 baking sheets with parchment paper. Working with 1 dough disk at a time, unwrap and place on a lightly floured surface. Roll out dough disk to 1/4-inch thickness. Using a 2-inch cookie cutter, cut each dough disk into 12 cookies. Transfer to prepared sheets, placing about 1 inch apart. Bake at 350˚F until puffed and slightly dark around edges, about 10 minutes. Cool on sheets 2 minutes; remove with spatula to a wire rack. Cool 10 minutes. Decorate with sprinkles.