01 - Preheat the oven to 350°F and line two baking sheets with parchment paper.
02 - Whisk together the gluten-free flour, baking soda, cream of tartar, and salt in a medium bowl.
03 - Beat the softened butter, granulated sugar, and brown sugar until light and fluffy, approximately 2-3 minutes.
04 - Add the egg and vanilla extract, mixing until fully incorporated.
05 - Gradually add the dry ingredients to the wet mixture, mixing until a soft dough forms.
06 - Mix the granulated sugar and ground cinnamon in a small bowl for coating.
07 - Scoop tablespoon-sized portions of dough, roll into balls, and coat each ball thoroughly in the cinnamon-sugar mixture.
08 - Place the dough balls 2 inches apart on the prepared baking sheets.
09 - Bake for 9-11 minutes, or until edges are set and centers appear slightly soft.
10 - Let cookies cool on the baking sheet for 5 minutes before transferring to a wire rack to cool completely.