In a medium bowl, whisk together flour, cream of tartar, baking soda, salt, and pumpkin pie spice.2 3/4 cups all-purpose flour,2 teaspoons cream of tartar,1 teaspoon baking soda,1/2 teaspoon salt,1 teaspoon pumpkin pie spice.
In a large bowl, cream together butter and 1 1/3 cups sugar until light and fluffy.1 cup unsalted butter,1 1/3 cups granulated sugar.
Beat in the egg, pumpkin puree, and vanilla extract until well combined.1 large egg.3/4 cup pumpkin puree,2 teaspoons vanilla extract.
Gradually mix in the dry ingredients until just combined.
Cover the dough and refrigerate for at least 30 minutes.
Preheat oven to 350°F. Line baking sheets with parchment paper.
In a small bowl, mix 1/4 cup sugar and cinnamon for rolling.1/4 cup granulated white sugar,2 teaspoons ground cinnamon.
Roll chilled dough into 1-inch balls, then roll in the cinnamon-sugar mixture.
Place on prepared baking sheets, about 2 inches apart.
Bake for 9-11 minutes, until edges are lightly golden.
Let cool on the baking sheet for 5 minutes before transferring to a wire rack.
Notes
Pro Tip: Don’t skip the chill time. Pumpkin makes this cookie dough softer than traditional snickerdoodle dough, and chilling it for 30 minutes makes it easier to roll while helping the cookies hold their shape as they bake.