Sourdough Shortbread Cookies

Beat the softened butter and powdered sugar in the bowl of a stand mixer fitted with the paddle attachment (or a hand mixer) for a few minutes until light and fluffy. Scrape down the sides of the bowl with a spatula if needed.
Add the vanilla extract and sourdough discard and mix until combined.
226 g Unsalted Butter, 113 g Powdered Sugar, 120 g Sourdough Discard, 2 tsp Vanilla Extract
In another bowl, combine the dry ingredients.
Then, add to the stand mixer bowl and mix just until combined. The cookie dough will be crumbly and have a consistency similar to Play-Doh when squeezed.
260 g All-purpose flour, ½ tsp Kosher Salt, 2 TBS Cornstarch
Scrape the dough out onto a work surface and divide it in half.*
Roll the dough halves into about 5" squat logs with your hands (flour to prevent sticking) and place them each in the center of a large piece of parchment paper.
Fold the parchment over the log and use a bench scraper or other straight edge to push the log into a tight cylinder. This will lengthen the log and pack it, eliminating bubbles and gaps, resulting in perfectly round slices. The logs should be about 10 inches long.
Wrap the log in the parchment paper, then place it onto a large piece of plastic wrap and twist the ends to further pack the log ends and keep it safely wrapped in the refrigerator.
Chill the logs for at least an hour in the refrigerator or freeze them months in advance.
Preheat the oven to 350ºF (177ºC) and line baking sheets with parchment paper.
For crunchy, sparkly cookie edges, sprinkle raw sugar on a clean cutting board. Unroll the chilled shortbread dough, then roll the logs in raw sugar.
If the coating isn’t sticking, brush the logs with egg white to help the sugar adhere.
Then, use a sharp knife to trim the ends of the logs and then cut into ¼”-⅜” thick slices. Each log usually makes about 13-15 cookies.
To help the cookies keep their round shape while cutting, rotate the log a quarter turn in between each slice.
Space the cookies a couple of inches apart on the prepared baking sheets.
Bake for 18-20 minutes or until the edges and bottom of the cookies just start to brown. They will continue to set and harden as they cool.
Let the cookies cool on the pan for a few minutes, then transfer them to a wire rack to cool completely.

Equipment

Ingredients

Instructions

Notes