In a small-medium mixing bowl, whisk together the flour, salt, 1 ½ tsp of the pumpkin pie spice, and the baking soda until combined. Set aside.

In a large mixing bowl, whisk together the melted butter, brown sugar, and ¼ cup of the white sugar for about 1 minute.

Whisk in the egg and egg yolk, and the vanilla until combined.

Stir in the pumpkin puree and sourdough discard until well combined.

Fold in the dry ingredients into the wet ingredients until everything is just combined and the cookie dough has formed. Cover the dough with plastic wrap and refrigerate for 2 - 3 hours or up to overnight.

When ready to bake, preheat the oven to 350 degrees Fahrenheit and line a baking sheet with parchment paper.

Mix together the remaining ¼ cup sugar and 1 tsp of pumpkin pie spice until combined.

Divide the cookie dough evenly between 12 dough discs, and roll each ball/disc into the sugar mixture, then place on the baking sheet.

Bake cookies for 12 - 14 minutes or until the cookie has spread evenly, the edges are golden brown, and the middle is still slightly soft.

Let cool for about 10 minutes on the pan, then transfer to a cooling rack to finish cooling.