Preheat the oven to 375F. Line two baking sheets with parchment paper or a silicone baking mat. Set aside.

In a mixing bowl, combine the gluten-free flour blend, xanthan gum (if using), baking powder, cream of tartar, cinnamon and salt. Whisk together. Set aside.

In a separate mixing bowl, add the brown sugar, granulated sugar, and softened butter.

Cream together for 2-3 minutes, until light and fluffy.

Add the eggs and vanilla extract. Mix until smooth, scraping down the sides and bottom of the bowl to ensure everything gets incorporated.

Gradually add the dry ingredients to the wet ingredients. Stir in between each addition. Mix until no more streaks of flour remain. Chill the dough for 30 minutes.

In a small bowl, combine the granulated sugar and ground cinnamon for the topping.

Roll the cookie dough into 2 tablespoon dough balls, about 1-inch in diameter. If you’re weighing the cookie dough balls, they should weigh about 42 grams or 1.5 oz each.

Roll the cookie dough balls into the cinnamon sugar mixture.

Place the snickerdoodle dough balls on the prepared baking sheet, leaving about 3 inches in between each ball so it has room to spread. I typically can fit about 6 cookies on a sheet pan at a time.

Bake at 375F for 9-11 minutes, until the edges are set and the center of the cookie dough no longer looks shiny. Do not over bake.

Let cool for 5 minutes on the baking sheet before transferring to a wire rack to finish cooling completely. Repeat with remaining cookie dough.