01 -
Preheat your oven to 350°F (180°C) or 320°F (160°C) fan/convection. Line two baking sheets with parchment paper. In a medium bowl, whisk together the flour, baking powder, and salt. Set aside. Roughly chop the dark chocolate into small chunks.
02 -
Create a double boiler by setting a heatproof bowl over a pot of barely simmering water (make sure the bowl doesn't touch the water). Add the chopped chocolate, butter, cocoa powder, vanilla extract, and espresso powder to the bowl. Stir occasionally until completely melted and smooth. Remove from heat and let cool slightly for about 5 minutes.
03 -
In a large bowl, beat the brown sugar, granulated sugar, and eggs with an electric mixer on medium-high speed for 4-6 minutes until the mixture is pale, thick, and falls in ribbons when the beaters are lifted. This step is crucial for the crackly top! Gently fold in the slightly cooled chocolate mixture until well combined. Add the flour mixture and fold just until no dry streaks remain, being careful not to overmix.
04 -
Using a cookie scoop or spoon, portion the dough into 12 equal mounds on the prepared baking sheets, leaving about 2 inches between each cookie as they will spread. Sprinkle each cookie with a few flakes of sea salt. Bake for 16-18 minutes, until the edges are set but the centers still look slightly underdone (they'll continue cooking as they cool). For perfectly flat cookies with that beautiful crinkly top, firmly tap the baking sheets on the counter a few times immediately after removing from the oven.