In your mixing bowl or stand mixer, cream the softened butter and granulated sugar for 2 full minutes until pale and fluffy. This is key in achieving the texture we want in our cookies!
¾ (170g) cup unsalted butter, softened, 1¼ (250g) cups granulated white sugar
Beat in the egg until fully emulsified in your cookie dough.
1 large egg
Mix the sourdough discard, vanilla extract, lemon extract, lemon juice, and lemon zest into the cookie dough until smooth.
⅓ (80g) cup sourdough discard (100 % hydration), 1 tsp vanilla extract, 1 1/2 tsp lemon extract, 1 (12g) Tbsp fresh lemon juice, Zest of 2 large lemons
In a separate bowl, whisk together the flour, cornstarch, baking soda, and salt. This is important to make sure your ingredients are evenly distributed. Gradually add the dry ingredients to the wet mixture, mixing on low speed until just combined. Avoid overmixing the cookie dough to ensure a tender cookie texture. The dough should be soft but thick.
3 (375g) cups all-purpose flour, 1/2 tsp cornstarch, ¾ tsp baking soda, ¾ tsp fine sea salt
Chilling of this dough is key to a a perfect cookie. Cover the mixing bowl with plastic wrap or a lid and refrigerate the dough for at least 3 hours. You can scoop and bake after this chilling period, but don't skip the chill or your cookies won't hold their shape.
Overnight Fermentation Option: For optimal fermentation, consider chilling the dough overnight. If chilling overnight, allow the dough to rest at room temperature for about 10 minutes before baking to make scooping easier and ensure the right consistency of your cookies.
Note about refrigerating dough: If you want to scoop and refrigerate dough as balls, I recommend chilling 1-2 hours then scooping. Gram weight for these cookies is roughly 60-70 grams. Refrigerate scooped cookie balls up to 2 days before proceeding with baking.
Note about freezing dough: If you choose to freeze the cookie dough, I recommend refrigerating the dough after mixing until it firms up (about 1-2 hours). Scoop your cookies and refrigerate overnight to achieve optimal fermentation. If you wish, you can skip this refrigeration step, but your dough won't ferment as long. After dough has refrigerated, transfer to airtight containers or zip locks with air removed and freeze. When ready to bake cookies, allow cookie dough to rest 20 minutes at room temperature and bake cookies as directed below.