• Preheat your oven to 350°F (175°C)

Brown your butter:

• Add the chopped butter to a medium saucepan (preferably with a light bottom so you can track the color). Melt over medium heat, swirling occasionally, until the butter starts to foam. Once your butter starts to foam, stir continuously until it turns golden brown with dark specks at the bottom and smells deeply nutty, about 5 to 7 minutes.
• Immediately take the pan off the heat, and transfer to a heat proof bowl or measuring cup. Let sit for 10 minutes to cool

Sugar coating

• Combine the sugar, cinnamon, and pumpkin pie spice together in a small bowl. Set to the side

Cookie dough

• Mix together dry ingredients in a bowl. AP flour, pumpkin pie spice, cinnamon, baking soda, 1 tsp cream of tartar, and the salt. Set to the side.
• In a separate bowl, using whisk, mix together your cooled browned butter, granulated sugar, and brown sugar. Add the egg yolk, pumpkin puree, and vanilla extract. Mix just until combined
• Add the dry ingredients to the wet ingredients in three parts. Fold together gently.
• Roll cookie dough into 8 balls. Each weighing 65 grams. Roll each cookie dough ball in cinnamon-sugar coating.
• Place a few inches apart on your baking sheet. 
• Bake cookies for 12 minutes. The cookies will be very soft and tender fresh out of the oven. Allow to cool for 10 minutes on the baking sheet before transferring them to a wired rack.

Optional: mascarpone topping

• In a mixing bowl, whisk the mascarpone with the powdered sugar and vanilla just until combined and creamy (don’t over-beat or it can loosen).
• In a separate bowl, whip the heavy cream until it just holds soft peaks. You can use a stand mixer for this, but watch it closely; heavy cream can go from perfectly whipped to grainy very quickly.
• Gently fold the whipped cream into the mascarpone mixture until smooth and fluffy.
• Chill for 15–20 minutes before spreading or piping onto your cookies if necessary

Lastly

• If you choose to add the topping, pipe the mascarpone cream on to your cooled cookies, add a dusting of pumpkin pie spice on top and you're done!

How to store them

• Store the cookies in an airtight container. At room temperature, they should stay fresh for about a week. (without mascarpone topping)