Preheat the oven to 375°F. Line two baking sheets with parchment paper and set aside.
In a medium bowl, whisk together 2¾ cups (385 g) gluten-free flour blend, 2 teaspoons (6 g) cream of tartar, 1 teaspoon (4 g) baking soda, 1 teaspoon (6 g) salt, and 1 teaspoon (2 g) ground cinnamon. Set aside.
In a large bowl, cream 1 cup (227 g) unsalted butter, 1 cup (220 g) brown sugar, and ¾ cup (150 g) granulated sugar together with an electric mixer for 2 to 3 minutes, until light and fluffy.
Add 2 (100 g) large eggs and 2 teaspoons (8 g) vanilla extract. Mix until smooth, scraping down the sides of the bowl as needed.
Gradually add the dry ingredients to the wet ingredients, stirring between each addition, until no streaks of flour remain.
Cover the dough and refrigerate for 30 minutes.
In a small bowl, combine ¼ cup (50 g) granulated sugar and 1 tablespoon (8 g) ground cinnamon for the coating.
Scoop the dough into 2-tablespoon balls (about 1.5 oz/42g each). Roll each ball in the cinnamon sugar mixture until fully coated. Keep the remaining dough in the refrigerator between batches.
Place the dough balls on the prepared baking sheets, leaving about 3 inches between each one. Bake 6 cookies per sheet for 9 to 11 minutes, until the edges are set and the center no longer looks shiny. Do not overbake.
Let cool for 5 minutes on the baking sheet before transferring to a wire rack. Repeat with the remaining dough.