01 -
Preheat oven to 160°C (fan) or 170°C (conventional). Line a baking tray with parchment paper.
02 -
In a heatproof bowl, combine chopped dark chocolate and butter. Set over a pan of simmering water, ensuring the bowl does not touch the water. Stir occasionally until fully melted. Remove from heat and stir in the vanilla extract.
03 -
In a medium bowl, beat eggs, caster sugar, and Demerara sugar using an electric whisk on high speed for about 5 minutes, until thick and pale.
04 -
Sift flour, cocoa powder, baking powder, and salt into a bowl. Stir in chocolate chips to evenly distribute.
05 -
Gradually fold the melted chocolate and butter mixture into the whipped eggs and sugars, taking care to keep the batter airy.
06 -
Carefully fold the dry ingredient mixture into the wet batter using a spatula. Mix only until just combined to preserve the light texture.
07 -
Scoop tablespoons of batter onto the lined baking tray, spacing well apart. Bake in the preheated oven for 12–14 minutes, or until tops are set and crackled.
08 -
Remove from oven; if desired, sprinkle with sea salt. Let cool on the tray for 10 minutes before transferring to a wire rack to cool completely.