Prepare the Pumpkin Puree

You can complete this portion of the recipe up to 48 hours in advance – allow it to cool at room temperature, then store the reduced pumpkin puree covered in the fridge until it’s needed when you make the cookie dough.

1. In a small saucepan, add the pumpkin puree (1/2 cup) and pumpkin pie spice (2.5 teaspoons) and stir together with a heat-proof spatula until combined.
   
2. Gently stir, constantly, over medium heat for about 15 minutes until the pumpkin has darkened to a deep rust color, the spices are fragrant, and enough moisture has been released so that you have about 1/3 cup of puree remaining.

   It will feel like nothing is happening for about the first ten minutes, but trust the process and keep stirring. If you don’t stir constantly, you run the risk of the pumpkin burning to the bottom of your pan.

   If it feels like things are cooking too quickly or are starting to burn, remember that you are in control of the heat! Lower the heat a bit until you feel like you’re back in control and keep going.

   When finished, it will resemble a thick paste like tomato paste that holds its shape when you push it around the pan.
   
   

3. Remove from heat, check that you have about 1/3 cup (it’s worth taking the extra couple of minutes to measure it out!), and allow to cool until it’s used later in the recipe.
   

Make the Dough

1. In the bowl of a stand mixer fitted with the paddle attachment, add the unsalted butter (8 Tablespoons – softened), granulated sugar (3/4 cup), and light brown sugar (1/4 cup – packed) and beat on medium speed (level 4 on a KitchenAid mixer) until lightened to a creamy off-white color and fluffy in texture.

   In my experience, this can take anywhere from 4-8 minutes (use these numbers as a guide, not a rule), depending on how soft your butter is. I scrape down the bowl regularly with a flexible spatula to ensure all of the butter and sugar are creamed together evenly. 

2. With the mixer on low, add the egg yolks (2) and mix until there are no shiny streaks and everything is thoroughly combined.
3. Pause the mixer, add the vanilla extract (1 teaspoon) and the cooled pumpkin puree. Mix on low until everything is combined, scraping down the bowl and paddle as needed.
4. In a medium-sized bowl, add the all-purpose flour (2 cups + 2 Tablespoons – spooned and leveled, see Note*), cornstarch (1 Tablespoon), kosher salt (1/2 teaspoon), baking soda (1/2 teaspoon), and cream of tartar (1/2 teaspoon). Whisk together thoroughly until everything is combined – about 30 seconds.

   These are your dry ingredients.

5. Add the dry ingredients to your mixing bowl and mix on low until there are no dry flour patches and everything is combined.
6. Portion out the dough using a small cookie scoop, place on a plate and chill, covered, for 2 hours.

Bake the Cookies

1. Preheat your oven to 350°F. 
2. With clean hands, roll the portioned chilled dough between the palms of your hands so that each scoop becomes a smooth ball.

   If you’d prefer not to touch the dough with your bare hands, that’s totally fine and this step can be skipped. The cookies just might spread a little different compared to what you see in the pictures in this post.

3. In a small bowl, combine the granulated sugar (1/4 cup) and ground cinnamon (1 teaspoon) and stir until fully combined.
4. Before placing the dough on a baking sheet lined with parchment paper to bake, gently roll each ball in the cinnamon sugar mixture and then bake for for 10-14 minutes, or until they feel like puffed marshmallows when you lightly tap the top of the cookies with the pad of your finger.

   To get a gooey center, you want them slightly under-baked

   If you prefer not to touch the dough with your hands to roll it in the cinnamon sugar mixture, you can pour the cinnamon sugar in a plastic baggie and toss the dough in the sugar that way, one at a time.