Sourdough Black and White Cookies

In a medium-sized mixing bowl, whisk the flour, salt, baking powder, and baking soda. Set aside.
225 g All-purpose Flour, ½ tsp Baking Powder, ½ tsp Baking Soda, ½ tsp Kosher Salt
In the bowl of a stand mixer fitted with the paddle attachment (or in a large bowl with an electric hand mixer), cream the softened butter and sugar together until light and fluffy.
Add the lemon zest, egg, egg yolk, vanilla extract and mix on low speed for a minute until combined. Then, pour in the sourdough discard and buttermilk and mix for a couple of minutes. Scrape the sides of the bowl if needed.
Turn off the mixer and dump in the bowl of dry ingredients. Then, slowly pulse to incorporate and mix for a minute or two just until the flour is completely hydrated.
113 g Unsalted Butter, 150 g Granulated Sugar, ½ tsp Lemon Zest, 1 Egg, 1 Egg Yolk, 2 tsp Vanilla Extract, 120 g Sourdough Discard, 56 g Buttermilk
Chill the cookie dough batter for at least 20 minutes in the refrigerator.* This will help the cookies not spread as much.
As the cookies chill, preheat the oven to 350ºF (177ºC) and move an oven rack to the middle of the oven for even baking.
Line a couple of baking sheets with parchment paper or silicone baking mats.
Use a cookie scoop to evenly portion out about 3 TBS of cold cookie dough. Space the cookies a few inches apart on the baking sheets as they do spread as they bake.
Bake one sheet at a time for 14-15 minutes until the tops are spongy and the bottoms brown slightly. Cool completely on a wire rack and repeat with the other baking sheet.
As the cookies bake and cool, make the icing.
Sift the powdered sugar into a medium bowl and whisk in the salt, corn syrup, hot water, and vanilla extract. The icing should be quite thick, glossy, and hold the trails of the whisk in the bowl.
If too thick, add a splash or two of hot water. If too runny, add more confectioner's sugar.
240 g Powdered Sugar, 3 TBS Light Corn Syrup, 1 tsp Vanilla Extract, 2 TBS Hot Water, 1 pinch Salt
Once the cookies are completely cool, ice the flat sides of the cookies (the bottoms). Ice the vanilla halves first and then ice the chocolate halves using the same bowl of icing.
For even and straight lines, use an offset spatula dipped in the icing and let a thin line of vanilla icing run straight down the middle half of one cookie. Then, fill in a half with vanilla icing in a thin, even layer. Lay the half-iced cookies on a wire rack for at least 20 minutes to let the vanilla icing set and dry.
Once the vanilla icing is set, sift the cocoa powder into the same icing mixture. Whisk in another tablespoon or two of hot water until it's the same consistency as the vanilla icing. Finally, finish icing the remaining half of the cookies. Let the icing set for at least 20 minutes before enjoying (if that's possible!).
23 g Dutch-process Cocoa Powder

Sourdough Black and White Cookies

Equipment

Ingredients

Sourdough Black and White Cookies

Vanilla and Chocolate Icing

Instructions

Notes