Step 1

Brown the Butter: Heat the butter in a small to medium-sized pan on the stove over medium heat. Swirl the butter around and stir every minute. The butter will bubble up and fairly quickly, and you will notice a nutty smell and see little brown flecks appearing on the bottom of the pan when you stir the butter. Immediately remove the pan from the stove (the butter can burn quickly if left for too long on the stove).Pour the brown butter along with all the little brown bits on the bottom of the pan into a medium sized bowl and let sit for a few minutes to cool.Note: Melted butter can be substituted for the browned butter if you prefer.

Step 2

Mix Wet Ingredients: Add brown sugar and granulated sugar to the bowl. Mix together with a kitchen spatula or wooden spoon. Add the sourdough discard and stir together to combine completely. Mix in the egg yolk and vanilla extract until smooth and combined.

Step 3

Mix Dough: To a small bowl, add the flour, baking soda, baking powder and salt and fluff together. Pour the flour mixture into the butter mixture and mix together until just combined. Add chocolate chips and stir into the dough until evenly dispersed.

Step 4

Scoop and Chill Dough Balls: Scoop the dough into balls and place on a parchment-lined baking sheet or in an air-tight container. Cover the cookie dough balls and place into the refrigerator to chill for about 30 minutes to 1 hour. Alternatively stick the dough balls in the freezer and chill for 15-20 minutes before baking. It is possible to bake these cookies right away, but they will not be quite as thick and will spread a lot more than the chilled dough, resulting in a thinner and crispier cookie. You can also chill/long-ferment the dough in the refrigerator for up to 72 hours. Dough can be frozen and stored for 3 months. Let the balls come back to "chilled" temperature before baking.

Step 5

Bake Cookies: Preheat oven to 375ºF convection or 400ºF non-convection (see recipe note). Place 12 dough balls on a parchment-lined baking sheet, spread apart so they won't bake into each other. Add a few more chocolate chips to the top of each cookie if desired. Bake cookies for 7-8 minutes until edges are crispy and cookies are puffed up. The middle will still be a little gooey. Sprinkle the tops with flaky sea salt if desired. Let the cookies sit for about 5-10 minutes on the baking sheet to set up before removing to a cooling rack. Note: If you want uniform, circular cookies, take a round biscuit cutter and place it around one of the hot cookies straight out of the oven. Move your hand around in a cricle around the hot cookie.

Step 6

Repeat with the remaining cookie dough balls and enjoy. These cookies are especially delicious still slightly warm from the oven.