Add granulated sugar and brown sugar to a bowl with the cooled brown butter (from above) and whisk (or beat) until combined, about 1 to 2 minutes.
⅔ cup granulated sugar, ½ cup dark brown sugar
Add the "dried" pumpkin (from above), egg yolk and vanilla extract and mix until thoroughly combined.
1 egg yolk, 2 teaspoons vanilla extract
In a separate bowl, whisk together the flour, cream of tartar, baking soda, pumpkin pie spice and salt.
2 cups all purpose flour, 1 ½ teaspoons cream of tartar, 1 teaspoon baking soda, 1 ½ teaspoons pumpkin pie spice, ½ teaspoon fine sea salt
Gradually add flour mixture to pumpkin mixture, stirring until well combined. Refrigerate dough for at least 20 to 30 minutes or until dough is no longer soft.