Weigh or measure into a bowl the flour, cream-of-tarter, salt, baking soda, and the pumpkin pie spice then whisk together and set it aside.
Next, weigh or measure the sugar and add to a stand mixer that has the paddle attachment in place. I cut the room temperature unsalted butter into slices and add to the sugar. Start on low to get the butter and sugar mixed than I put the mixer on 6 (medium speed) till the sugar-butter mixture is light and fluffy. Turn off and scrape the sides down.
Add the egg and beat till incorporated, stop the mixer and add the pumpkin puree. You can also scrape the sides down again if it needs it. Mix the pumpkin puree till everything is a nice pumpkin color about 30 seconds to a minute.
Turn the mixer to low and slowly add the flour mixture to the pumpkin puree, sugar, egg, and butter mixture. Blend till the flour is incorporated, don't over mix it but you want all the flour mixed in. Scrape down the side and put in the refrigerator for about ½ hour.
Preheat the oven to 400°. Mix your ¼ cup of sugar with the ground cinnamon in a shallow bowl and set aside.
Take the dough out of the refrigerator (it will be soft) and I use a teaspoon with the long handle that you use for ice tea to scoop out enough dough to roll in my hand to make 1 ½" ball. Roll it in the sugar and cinnamon mixture to coat and put on a cookie pan that is lined with parchment paper. I get 12 to a cookie sheet if you place them about 2" apart.
I always bake 1 pan at a time and this is no exception. Bake for 10-12 minutes and transfer to a cooling rack right after pulling them out of the oven. Enjoy!