Preheat oven to 350°F (175°C) and line a baking sheet with parchment paper.
Whisk flour, cream of tartar, baking soda, and salt in a bowl. Set aside.
In another bowl, beat butter and sugar until fluffy.
Add eggs, vanilla extract, and espresso powder. Mix until combined.
Gradually add dry ingredients, stirring until fully incorporated.
Mix sugar, cinnamon, and espresso powder in a separate bowl for rolling.
Scoop dough into 1-inch balls and roll in the sugar mixture.
Place on a baking sheet, spacing them 2 inches apart.
Bake for 10 minutes or until the edges are lightly golden.
Cool before inhaling the entire tray.