In medium mixing bowl, whisk together brown rice flour, sweet rice flour, tapioca starch, ground ginger, ground cinnamon, baking powder, salt, ground clove, and xanthan gum. Set aside. In bowl of stand mixer fitted with paddle attachment, cream together butter and dark brown sugar until a thick paste forms, about 30 seconds. Add egg. Blend until combined. Stop mixer and scrape down bottom and sides of the bowl. Add dry ingredients. Blend until a thick dough forms. Add molasses. Blend until thoroughly combined.

Lightly flour your countertop with brown rice flour. Turn dough out onto counter and pat into a round. Wrap tightly with plastic wrap. Chill for several hours or overnight.

Preheat oven to 350°F. Remove dough from the refrigerator and allow to stand for five minutes. Divide dough round in half and roll out to 1/4-inch thickness on a generously rice floured countertop. Cut into shapes. Place cookies on parchment-lined baking sheet. Bake until edges are golden brown and aromatic, about 12 minutes. Repeat with remaining dough.

Cool cookies on a wire rack. Decorate as desired. Store cookies in a covered container for up to one week.