Ingredients
3 cups flour
2 tsp. cream of tartar
1 tsp. baking soda
1⁄4 tsp. kosher salt
1 3⁄4 cups sugar
16 tbsp. unsalted butter,
at room temperature
5 tsp. ground cinnamon
1 1⁄2 tsp. vanilla extract
2 eggs
Preparation
In a medium bowl, whisk together flour, cream of tartar, baking soda, and salt; set aside. Using a handheld mixer on medium speed, beat 1 1⁄2 cups sugar and the butter together in a medium bowl until pale and fluffy, 2 minutes. Add 2 tsp. cinnamon and the vanilla; beat for 1 minute more. Add eggs one at a time, beating well after each addition. Add reserved dry ingredients; mix on low speed until just combined. Refrigerate dough for 30 minutes.
Heat oven to 375°. Combine remaining sugar and cinnamon in a small bowl. Remove dough from refrigerator and, using a 1-tbsp. measure, spoon out 48 portions, rolling each portion into a 1" ball as you go. Roll each ball in cinnamon-sugar mixture to coat. Arrange dough balls 2" apart on 2 parchment paper-lined baking sheets. Bake until golden brown, about 10 minutes. Transfer to a rack and let cool.
