In a mixing bowl, whisk together flour, cornstarch, cream of tartar, baking soda, salt, cinnamon, ginger, nutmeg, and cloves for 20 seconds. Set aside.

In the bowl of an electric stand mixer fitted with the paddle attachment (or in a mixing bowl using an electric hand mixer), cream together butter, brown sugar, and granulated sugar until well blended.

Mix in egg yolk, then mix in pumpkin and vanilla extract. Scrape down the mixing bowl.

With the mixer set on low speed, slowly add in the dry ingredients, then mix until combined.

Spread the dough up the sides of the bowl with a well in the center for even chilling. Cover and chill for 45 minutes to 1 hour.

Preheat oven to 350°F (175°C) during the last 15 minutes of refrigeration.

In a small bowl, whisk together the cinnamon sugar coating ingredients.

Scoop dough out about 2 tablespoons at a time and shape into a ball. Roll the dough ball in the cinnamon sugar mixture to evenly coat, then transfer to parchment paper-lined baking sheets, spacing cookies 2 inches apart.

Bake in the preheated oven for 12-14 minutes (they should look just slightly under-baked as they'll cook slightly once removed from the oven). Cool on the baking sheet for about 5 minutes, then transfer to a wire rack to cool completely.