Mill your flour into a small bowl and set aside.
In a large bowl sift the powdered sugar.
To your sifted powdered sugar add the sourdough discard, vanilla, and butter.
Cream this using a hand mixer or stand mixer until well combined.
To your freshly milled flour, add the salt and chopped nuts. Stir to combine.
Add your dry mix to your wet mix, mixing in half before adding the other half. Do not overmix.
Cover with a towel or plastic wrap and allow this to rest for 30 mins before baking. To further increase the benefits of the sourdough, transfer to the refrigerator for 12-24 hours. Chilling before baking isn't required for these, they hold their shape well and are easy to scoop out using a cookie scoop or spoon.
When ready to bake, preheat oven to 350°F.
Line a baking sheet with parchment or a silicone baking sheet.
Using a standard sized cookie scoop or a spoon, scoop out dough balls roughly 1.5-2 inches.
Bake for 15-23 minutes depending on the size of your cookie balls. Bottom edges of the cookies should be golden brown.
As soon as the cookies have cooled enough to touch, roll them in the powdered sugar. Make sure you do this before they have cooled completely.
Once they have cooled, roll them in the powdered sugar a second time.