Steps

• In a medium bowl, whisk together the all-purpose flour, cornstarch, cream of tartar, baking soda, salt, ground cinnamon, ground nutmeg, and ground cloves until well combined.
• In a large bowl, use an electric mixer to beat together the room temperature unsalted butter, packed light brown sugar, and white sugar until the mixture looks light and fluffy.
• Reduce the mixer speed to low and beat in the egg, pure vanilla extract, and canned pumpkin until everything is incorporated.
• Gradually add the dry mixture into the wet mixture, mixing until a very sticky dough forms.
• Cover the bowl with clingfilm and refrigerate the dough for at least 2 hours, or up to 2 days.
• Preheat your oven to 350°F (175°C) and line two cookie trays with parchment paper or silicone baking mats.
• Whisk together the white sugar and ground cinnamon to make the cinnamon sugar coating.
• Form the chilled dough into balls, each about 1.5 tablespoons in size. Roll each ball in the cinnamon sugar coating and then flatten them slightly. Arrange on the lined baking trays, spacing them about 2 inches apart.