01 -
Preheat oven to 320°F with convection or 338°F for standard baking. Line a baking tray with parchment paper.
02 -
Combine chopped dark chocolate and butter in a heatproof bowl set over simmering water. Stir until completely melted and smooth. Remove from heat and mix in vanilla extract.
03 -
In a separate bowl, use an electric mixer on high speed to beat eggs, granulated sugar, and Demerara sugar until very light and fluffy, about 5 minutes.
04 -
In another bowl, sift together flour, cocoa powder, baking powder, and salt. Add chocolate chips and stir to distribute evenly.
05 -
Gently fold the melted chocolate and butter mixture into the whipped egg and sugar mixture, taking care not to deflate the volume.
06 -
Carefully fold the dry ingredients into the wet mixture using a spatula until just combined. Avoid overmixing.
07 -
Scoop tablespoon-sized amounts of batter onto the prepared tray, leaving ample space between each. Bake for 12–14 minutes until set and crackly on top.
08 -
Remove from oven and, if desired, sprinkle lightly with sea salt. Allow to cool on the tray for 10 minutes before transferring to a cooling rack.