Preheat oven to 350 degrees and line baking pans with silicone mats or parchment paper.
In a small bowl, stir together ¼ cup sugar and 1 tablespoon ground cinnamon and set aside.
In a large bowl, combine the remaining sugar, shortening, butter and eggs and mix together.
Add in the gluten free flour, xanthan gum, cream of tartar, baking soda and salt. Stir until all the ingredients are completely combined.
Roll the dough into 1 ¼ inch balls, then coat the balls in the cinnamon-sugar mixture. (Note: It's helpful to first roll the dough into 12 balls, place on the prepared baking pan, then roll in the cinnamon-sugar mixture. Repeat the process for each additional pan.)
Bake for about 10 minutes until the cookies are a golden brown.
Remove from the baking pan and allow to cool on a wire rack.