In a medium bowl, use whisk or fork to gently com gluten-free flour, cream of tartar, and baking soda. Set aside.
In a large bowl, use a whisk or electric/stand mixer to cream together granulated, brown sugar, vanilla extract and salt until thoroughly combined.
Add eggs to the butter and sugar and mix until combined.
Pour dry ingredients into the large bowl and gently mix using a rubber spatula until the dry ingredients are completely incorporated. (If using an electric/stand mixer, make sure to mix in dry ingredients on a low setting and scrape the bottom of the bowl). Set aside.
At this time, preheat the oven to 350ºF and line baking sheets with parchment paper.
Roll the Cookies in Cinnamon Sugar
In a small bowl, us a fork to evenly combine granulated sugar, cinnamon, and salt.
Using a #50 cookie scoop, scoop the cookie dough and place in cinnamon sugar.
Roll the scoop of dough in cinnamon sugar until a ball forms and is evenly coated in cinnamon sugar.
Place rolled cookie dough on lined baking sheet and repeat.
Make sure to place the rolled cookie dough balls approximately 2-3 inches apart on the baking sheet. (I like to limit my baking sheets to 6-8 balls of dough).
Bake at 350ºF for 12 minutes or until cookies are puffed up and the edges show a slight golden color.
Transfer cookies to a wired rack to cool for 10 minutes and repeat the previous 3 steps with remaining dough.