Preheat your oven to 160°C (320°F) for fan-assisted baking, or 170°C (338°F) for conventional settings.

In a heatproof bowl set over a pot of simmering water, combine the chopped dark chocolate and butter. Stir gently until melted and smooth.

In a large mixing bowl, beat together room temperature eggs, caster sugar, and demerara sugar for about 5 minutes until pale and fluffy.

Sift together the plain flour, cocoa powder, baking powder, and salt in a separate bowl. Fold in the chocolate chips.

Gradually fold the melted chocolate and butter mixture into the egg and sugar mix. Combine gently.

Gently fold the dry ingredient mixture into the wet ingredients until just combined to avoid tough brookies.

Drop dollops of dough onto the lined baking tray, leaving space for spreading. Bake for 12-14 minutes, until tops are crackled but still soft.

Allow the brookies to cool on the tray for about 10 minutes, then transfer them to a wire rack. Optionally, sprinkle with sea salt.