Start by preheating your oven to about 160°C (320°F) for fan ovens or 170°C (338°F) for conventional ovens. Line a baking tray with parchment paper so the cookies don’t stick while baking.

Place the chopped dark chocolate and butter into a heatproof bowl. Melt them together gently in short microwave bursts or over a double boiler until smooth and glossy.

In a separate bowl, whisk the eggs with caster sugar and demerara sugar. Continue whisking until the mixture becomes thick and slightly pale with a ribbon-like texture.

Slowly pour the melted chocolate and butter mixture into the egg mixture. Stir gently until everything is fully combined and smooth.

In another bowl, mix flour, cocoa powder, baking powder, and salt. Gradually fold this mixture into the batter using a spatula until just combined.

Stir in the chocolate chips to create small bursts of chocolate throughout the batter. The mixture will become thick, which is exactly what you want for chewy brownies.

Using a spoon or cookie scoop, drop spoonfuls of batter onto the prepared baking tray. Leave space between each portion because the cookies will spread while baking.

Bake the brownies for about 12–14 minutes until the tops look crackly and the edges begin to set. The centers should still feel slightly soft when touched.

Remove the tray from the oven and allow the cookies to cool on the tray for about 10 minutes. After that, transfer them to a cooling rack to cool completely.