In the bowl of a stand mixer fitted with a paddle attachment, cream the butter and sugars together for 3-4 minutes.
Add the pumpkin, vanilla, and egg and mix on medium speed for another 1-2 minutes.
Sprinkle the flour, cream of tartar, baking soda, and salt directly into the bowl and mix until just combined.
Fold in the chocolate before using a cookie scoop to create and roll balls of dough (about 1 1/2 tbsp of dough per ball).
Mix the sugar and cinnamon together and then roll each dough ball in the cinnamon sugar before placing 2 inches apart on a lined cookie sheet.
Freeze the tray for 10 minutes before baking for 9-11 minutes at 350F.
Let cool on the tray for 5 minutes before transferring to a rack to cool completely. Enjoy!