Yield: 28 cookies
Preheat oven to 350 degrees F. Line baking sheets with parchment paper or silicone baking mat. Set aside.
In a large bowl, whisk together flour, cream of tartar, baking soda, and salt. Set aside.
In the bowl of a stand mixer fitted with a paddle attachment (or using an electric hand mixer), beat together butter, cookie butter, and sugar until smooth. Scrape down bowl as needed to ensure thorough mixing. Add eggs and continue to mix until well incorporated.
Add dry mixture in two additions. Mix on medium speed until cookie dough forms. Scrape bowl as needed.
Use a 1 1/2-tablespoon scoop ( #40 scoop) to portion out dough.
Coating: In a small bowl, mix together sugar and cinnamon.
Roll cookie balls into sugar coating mixture. Place cookie balls 2-inches apart of prepared baking sheet. Bake 10-12 minutes, until the edges of the cookies are set. Allow to rest in baking sheet for 3-5 minutes before transferring to wire rack to cool.
Enjoy cookies warm or at room temperature. Store cooled cookies in an airtight container for up to 4 days.