Preheat your oven to 160°C (320°F) with a fan or 170°C (338°F) if using a conventional setting. Line a baking tray with parchment paper.

In a heatproof bowl, combine chopped dark chocolate and butter. Create a double boiler and stir gently until fully melted and smooth, about 5-7 minutes. Remove from heat and mix in the vanilla extract.

In a separate mixing bowl, beat the eggs with caster sugar and demerara sugar until light and fluffy, about 5 minutes.

Sift together the plain flour, cocoa powder, baking powder, and salt. Stir in the chocolate chips.

Gently fold the melted chocolate and butter mixture into the egg and sugar blend. Then fold in the dry ingredients until just combined.

Using a tablespoon or cookie scoop, dollop batter onto the prepared baking tray. Bake for 12-14 minutes, until edges are set.

Allow the brookies to cool on the tray for about 10 minutes before transferring them to a wire rack to cool completely.