- 1 cup unsalted butter
- 1 cup light brown sugar, lightly packed
- 2/ 3 cup granulated sugar
- 2 teaspoons vanilla extract
- 2 large eggs
- 2 1/ 3 cups all purpose flour
- 2/ 3 cup unsweetened cocoa powder
- 1 tablespoon corn starch
- 1 teaspoon baking soda
- 1/ 4 teaspoon baking powder
- 2 teaspoons kosher salt
- 2 teaspoons espresso powder
- 1/ 4 cup granulated sugar
Melt the butter in a saucepan over medium heat. Continue to cook the butter, swirling occasionally, until the water has evaporated and nutty brown solids form at the bottom of the pan. Remove from the heat and scrape the browned butter into the bowl of your stand mixer. Cool at room temperature for 30 minutes.
Add the brown sugar and granulated sugar to the butter; the butter will still be liquid. With the paddle attachment, beat the butter and sugars together on medium speed, scraping the bowl occasionally, until thick and lightened in color, about 8-10 minutes. Beat in the vanilla and eggs.
In a separate bowl, sift together the flour, cocoa powder, corn starch, baking soda, baking powder, salt and espresso powder. With the mixer on low, add the dry ingredients and mix just to combine. Use a spatula to finish incorporating all the dry ingredients at the bottom of the bowl into the dough. The dough will be thick.
Cover and chill the dough for several hours (preferably overnight, to let the flavors come together).
Preheat the oven to 350 and line a baking sheet with parchment paper. Let the dough warm up to room temperature for about 15 minutes, then use a small cookie scoop to portion out the dough into 3 dozen cookies. Roll each ball in the 1/4 cup granulated sugar, place two inches apart on the baking sheet, and use something flat (like the bottom of a glass) to press each ball down into a flat disk.
Bake for 7-8 minutes. Cool for one minute on the baking sheet, then carefully transfer to a wire rack to cool completely. Store in an airtight container for several days, or freeze indefinitely.