Preheat the oven to 350 degrees.
Line a baking sheet with parchment paper. Set aside.
Using cold butter from the refrigerator, cut the butter into small chunks. Place into the bowl of stand mixer fitted with a paddle attachment. Cream together until the butter is smooth. Scrape down the sides and bottom of the bowl.
Add 1/2 cup of granulated sugar and 1/2 cup of brown sugar into the butter. Cream together until smooth. Add in the egg and mix until smooth. Scrape down the bowl as needed.
Sift together the flour, cinnamon, cream of tartar, and baking soda. Add the dry ingredients into the wet and mix well until combined. The dough will hold together nicely.
Using a 1.5 tablespoon sized spring loaded cookie scooper, scoop out level scoopfuls of dough. Roll the dough lightly between the palms pf your hands.
Place 1/4 cup of granulated sugar into a small bowl. Roll rounded scoops of dough into the sugar to coat the dough on all sides.
Place the cookies onto the prepared baking sheet, leaving 2" between cookies.
Bake for 8-9 minutes. The cookies will begin to flatten and develop the signature snickerdoodle cracking during the last few minutes of cooking.
Transfer the cookies to a wire rack to cool.