Cream butter and sugar together with an electric mixer or stand mixer with the paddle attachment.
Add egg, vanilla, and pumpkin puree and mix until smooth.
In a separate bowl combine flour, baking soda, cream of tartar, salt, cinnamon, and pumpkin spice.
Add the dry ingredients to the wet ingredients and mix just until cookie dough forms. It will be a soft dough.
Scoop dough using a medium cookie scoop (2 tablespoons) and roll each cookie dough ball in cinnamon and sugar.
Bake on an ungreased (or parchment paper-lined) baking sheet for 6 minutes. Remove the baking sheet from the oven and tap against the counter a few times to flatten the cookies.Return the cookies to the oven and bake for an additional 3-4 minutes.Tap against the counter once more (if necessary).
Allow cookies to sit on baking sheets for 2-3 minutes before transferring the cookies to a cooling rack.
Video
Notes
I only bake 6-9 cookies at a time on a cookie sheet to allow them to spread.
Tapping the baking sheets against the counter is optional, but helps to flatten the cookies. The pumpkin puree changes the texture, slightly, making them flatten less than a classic snickerdoodle. Tapping the baking sheets during and after baking will yield flat snickerdoodles with the crackly tops.
Storing and Freezing CookiesStore cookies in an airtight container for up to 3-5 days.Snickerdoodles freeze beautifully. Transfer the cookies to an airtight container and freeze for up to 3 months.