Preheat your oven to 350 F (180 C). Line two baking sheets with parchment paper.
In a medium bowl combine the flour, cocoa powder, salt and baking powder. Set aside.
In a heatproof bowl over a small pan of simmering water, melt together the chocolate and butter. Once melted, remove from the heat.
Using a hand mixer with the whisk attachment, whisk both sugars and the eggs on medium-high speed for 6-7 minutes or until tripled in volume.
Gently fold the chocolate mixture into the egg mixture until just incorporated.
Fold in the flour mixture using a spatula until just incorporated and no flour clumps remain. The batter will be very sticky.
Use a large (3 tablespoon) cookie scoop to transfer the batter to the lined baking sheets. Space them at least 1 inch apart as they will spread during baking.
Bake the cookies for 10 minutes.
Cool the cookies on the baking sheets for 5 minutes, then transfer to a wire rack to cool completely. Sprinkle with flaky salt.
Enjoy!
