Preheat oven to 375°F and line baking sheets with parchment paper.
In a large bowl, whisk together 1 cup granulated sugar, oil, eggs, and molasses.and vanilla.
In a separate mixing bowl, whisk together the flours and starches, xanthan gum, baking soda, spices, and salt.
Mix the dry ingredients into the wet ingredients, and stir until fully combined.
Roll 1 teaspoon of dough into a ball, and roll in the remaining sugar to coat. Place on prepared baking sheet, leaving 2-inches between cookies.
Bake in preheated oven for 8-10 minutes. Allow cookies to remain on cookie sheet for 2 minutes before transferring them to a cooling rack to cool completely. Once cooled, store cookies in an airtight container.
Recipe by Faithfully Gluten Free at http://www.faithfullyglutenfree.com/2012/10/crisp-gluten-free-gingersnap-cookies.html