Melt 226 g (1 cup/2 sticks) of unsalted butter over medium heat in a medium saucepan on the stove. Swirl the pan often and scrape the bottom of the pan with a heat-proof spatula until the butter foams and the milk solids turn golden brown, about 5-7 minutes.

Pour the melted butter into a large mixing bowl and wait a couple of minutes for the butter to cool. Add 300 g (1 1/2 cups) brown sugar and 100 gm (1/2 cup) granulated sugar to the bowl, stirring to incorporate.

Next, add 3 large egg yolks, 1 tbsp vanilla extract, and 125 g (1/2 cup) of sourdough starter discard to the bowl.

In a separate bowl, whisk together 282 g (2 1/4 cups) of all-purpose flour, 1 tsp baking soda, and 1 tsp salt. Fold the dry ingredients into the wet ingredients to combine. Lastly, stir in chocolate chips.

It's normal for the cookie dough to look more greasy than a traditional chocolate chip cookie dough.

Cover the bowl and place in the refrigerator to chill for at least 2 hours and up to 24 hours.

​Remove the dough from the fridge. Preheat the oven to 375°F/190°C and line a baking sheet with a piece of parchment paper.

Scoop the cookies using a cookie scoop and place them onto the prepare baking pan 2 inches apart.

Bake in the preheated oven for 9-10 minutes.

The edges of the cookies will be set and just start to turn a golden color, while the middle of the cookie will be puffy and have a glossy look. The cookies will look like they aren't done yet.

Tip: Be sure you don't overbake for chewy cookies. If you bake until they're golden brown, they will be overbaked, resulting in a crispy cookie.

Leave the cookies on the baking sheet for 2 minutes to finish baking. While they rest, sprinkle the tops of the cookies with a pinch of flaky salt and then transfer to a wire rack to cool. The cookies will be soft and fall apart easily while still warm but will firm up once fully cool.

Store cookies in an airtight container at room temperature. They are best eaten within 2-3 days, gradually drying out the longer they sit.