In a large mixing bowl, combine the cooled browned butter, brown sugar, and granulated white sugar. Using an electric mixer on medium speed, cream together for approximately 2 minutes until the mixture is well combined. It'll be a bit crumbly, that's okay!
1 (200g) cup granulated white sugar, 1 (200g) cup brown sugar
Measure out the pumpkin purée, then place it on a plate lined with paper towels. Use another paper towel to blot the pumpkin to remove as much liquid as possible. After blotting, you should have a thick pumpkin mixture. Don’t skip this step! It’s what helps keep these cookies chewy instead of cakey.
¾ (180g) cup pumpkin purée
You can also do this using a lint-free kitchen towel and squeezing out the extra water.
Add the egg yolk, vanilla, sourdough discard, and reduced pumpkin puree to the sugar butter mixture.
1 egg yolk , ⅓ (80g) cup sourdough discard, 1½ tsp vanilla extract
Mix all of the wet ingredients on LOW until just combined.
In a separate bowl, whisk together the flour, cream of tartar, baking soda, cinnamon, ginger, nutmeg, cardamom, and salt. You can substitute the spices for pumpkin pie spice blend, please see the notes to do this.
3 (350g) cups all-purpose flour, 2 tsp cream of tartar, 1 tsp baking soda, 1½ tsp ground cinnamon, ½ tsp ground ginger, ¼ tsp ground nutmeg, ⅛ tsp ground cardamom, ¾ tsp fine sea salt
Mix the dry ingredients into the wet ingredients on low just until no dry streaks remain. Avoid overmixing the cookie dough or the cookies will get tough.
Using a 2-ounce cookie scoop (approximately 4 tablespoons or 75g balls), portion out your cookie dough and roll into balls. Transfer to a parchment lined baking sheet, and cover with plastic wrap. Transfer to the refrigerator to chill.
Chilling of this dough is key to a a perfect cookie; make sure you chill the cookies at least 2 hours before you bake them for the best results.
Overnight Fermentation Option: For optimal fermentation, consider chilling the dough overnight. If chilling overnight, allow the dough balls to rest at room temperature for about 20 minutes before proceeding with baking as listed below.