In the bowl of a stand mixer with the paddle attachment, add the cocoa powder (be sure to use a sifter, as cocoa powder often has lumps!), sugar, light brown sugar and oil. Mix on low until combined.

90g (3/4c) unsweetened cocoa powder (Natural or Dutch-processed), 200g (1 c) sugar, 110g (1/2 c) light brown sugar, 100g (1/2 c) neutral oil

Next, add the eggs and egg yolk one at a time, beating on medium-speed until well combined. Then beat in the sourdough discard and vanilla extract.

2 eggs + 1 egg yolk, room temperature, 60g (1/4 c) sourdough discard, 4g (1 tsp) vanilla

In a large bowl, add the flour, baking powder, espresso powder (optional) and salt. Whisk until incorporated. You won't taste the espresso, but it enhances the chocolate flavor!

200g (1 1/4 c + 3 T) all-purpose flour, 8g (2 tsp) baking powder, .5g (1 tsp) espresso powder, 3g (1/2 tsp) salt

Add the flour mixture to the cocoa mixture while mixing on low speed and continue to mix until there are just a few streaks of flour left behind. Then, using a rubber spatula, scrape the sides of the bowl and fold in the last bits of flour until the flour is fully incorporated.

Cover the dough in the bowl with plastic wrap and chill in the fridge for a minimum of 4 hours (24 hours is best!). The cookie dough is quite sticky when just mixed, so don’t rush the chilling. It is important for the cookie dough to firm up.

When ready to bake, preheat the oven to 350 degrees F and line a rimmed baking sheet with parchment paper. Set aside. Place the white sugar and powdered sugar in two separate bowls.

200g (1 c) sugar, 130g (1 c) powdered sugar

Using a small cookie scoop or a tablespoon, scoop the chilled cookie dough (about 25 grams each) and roll into a smooth dough ball. First, roll the dough ball in the white sugar until fully coated, then roll into the powdered sugar until fully coated before placing it on the prepared baking sheet about 2 inches apart.

Be sure to coat the dough balls with the sugars JUST before baking. (Only prepare enough dough balls to fill the baking sheet. You can continue to prepare the next batch of plain dough balls, but cover and store them in the fridge while they wait to be baked. You want the dough to stay chilled.).

Sprinkle a little final dusting on powdered sugar on top of each cookie with a small strainer or spoon.

Bake the cookies for 10-12 minutes or until the edges are slightly crisp while the tops look puffed up and slightly wet. Allow them to cool for a few minutes on the baking sheet before placing them on a wire rack to cool completely. Enjoy!