Preheat oven: Preheat oven to 375°F (190°C). Line a baking sheet with parchment paper or a silicone ma
Whisk dry ingredients: Whisk together flour, baking soda, cream of tartar, and salt in a medium bowl.
Cream butter and sugar: In a large bowl, beat butter and sugars until light and fluffy, about 2-3 minutes.
Add eggs and vanilla: Beat in eggs one at a time, followed by vanilla extract.
Add pumpkin puree: Beat in pumpkin puree until well combined.
Gradually add dry ingredients: Gradually add dry ingredients to wet ingredients, beating until just combined.
Chill dough: Chill dough for at least 30 minutes or up to 2 hours.
Roll in cinnamon sugar: Roll dough into balls, about 1 1/2 tablespoons each. Then, roll balls in cinnamon sugar to coat.
Bake: Place balls onto prepared baking sheet, leaving about 2 inches of space between each cookie.
Bake: Bake for 10-12 minutes or until edges are set and centers are slightly soft.