1. Preheat the oven to 350 degrees F and line a rimmed baking sheet with parchment paper. Set aside.
2. In the bowl of a stand mixer with the paddle attachment, cream the room temperature butter, powdered sugar, vanilla extract, and sourdough discard on medium speed for about 2 minutes. It will look light and fluffy.

   You can also use a hand mixer.
   170 grams unsalted butter, room temperature, 70 grams powdered sugar, 4 grams vanilla extract, 50 grams sourdough discard
3. Add the flour, salt, and chopped nuts (optional) and mix on low speed, until just combined. Use a rubber spatula to scrape the sides of the bowl to incorporate all the dry ingredients. The cookie dough will be crumbly.
   280 grams all-purpose flour, 2 grams salt, 120 grams walnuts or pecans, finely chopped
4. With your hands or a cookie scoop, scoop the cookie dough and roll it into a smooth ball shape, about 2 inches wide or about 2 Tablespoons worth of cookie dough.
5. When you press the crumbly dough together, it will adhere together and form a round dough ball. For the best results, make sure there are no cracks in the dough ball. 
6. This cookie recipe will make 14-16 sourdough snowball cookies. 

Bake

1. Place dough balls 2 inches apart on the prepared baking sheet.
2. Bake in a 350-degree F oven for 21-23 minutes, or until the bottom of the cookie starts to show a little color. (It's better to undercook, rather than overcook!)
3. Dip the warm cookies straight out of the oven into a bowl of powdered sugar and cool on a wire rack. The powdered sugar may melt a little bit.
   43 grams powdered sugar, for decorating
4. Once the cookies have cooled slightly, roll the cookie balls again in the powdered sugar for a final dusting.