In a small stainless steel saucepan, brown the butter over medium-low heat. It should have a rich, amber color with brown specks and a nutty scent. Transfer brown butter to a small bowl and let it cool until it solidifies. You can speed up the process by refrigerating the bowl or placing it over another bowl filled with ice and stirring.
1 cup (226 grams or 2 sticks) unsalted butter
In a small bowl, whisk together the flour, baking soda, and kosher salt. Set aside.
2 cups (240 grams) all-purpose flour, 1 teaspoon (6 grams) baking soda, 1 teaspoon (6 grams) kosher salt
In a large mixing bowl, combine the solidified brown butter, brown sugar, and granulated sugar. Whisk until well combined. Add the eggs and whisk vigorously until the mixture becomes fluffy and lighter in color. Mix in the vanilla extract and sourdough discard until smooth.
¾ cup (150 grams) brown sugar, ¾ cup (150 grams) granulated sugar, 2 large (100 grams) eggs, 1 tablespoon (14 grams) vanilla extract, ⅓ cup (75 grams) sourdough starter discard
Add the dry ingredient mixture to the wet ingredients and whisk until no dry flour remains. Gently fold in the chocolate chips.
2 cups (340 grams) semi-sweet chocolate chips
Cover the cookie dough and refrigerate for at least one hour or up to 24 hours.
About 20 minutes before the cookie dough is done chilling, preheat the oven to 350°F. Line a rimmed baking sheet with parchment paper.
Drop 2 tablespoons of cookie dough onto the parchment-lined baking sheet, leaving at least 2 inches of space between each dough ball. Optionally, press a few extra chocolate chips onto each cookie before baking for a more aesthetic look.
Bake for 9-11 minutes until the edges are golden brown and the center appears slightly undercooked.
Let the cookies cool on the baking sheet for 5 minutes before transferring them to a wire rack to cool completely.