1. Preheat oven to 375°F (190°C) and line baking sheets with parchment paper.

2. In a medium bowl, whisk together flour, cream of tartar, baking soda, and salt.

3. In a large bowl, beat butter and 1 1/2 cups sugar until light and fluffy, about 2–3 minutes.

4. Add eggs one at a time, then beat in vanilla extract until smooth.

5. Gradually mix dry ingredients into the butter mixture on low speed until just combined.

6. Cover and refrigerate dough for 30–45 minutes.

7. Combine 1/4 cup sugar and cinnamon in a small bowl.

8. Roll tablespoon-sized dough portions into balls and coat in cinnamon-sugar mixture.

9. Place dough balls 2 inches apart on prepared sheets and bake for 8–10 minutes until edges are set and tops crackle.

10. Let cookies rest on baking sheet for 2 minutes, then transfer to a wire rack to cool completely.

11. Serve warm or store in an airtight container for up to a week.