Preheat the oven to 180°C (350°F). Line a square baking tin with baking paper, leaving some overhang to make removing the brownies easier once baked.
Melt the butter and dark chocolate together gently in the microwave or in a heatproof bowl over a saucepan of simmering water. Stir until smooth, then allow to cool slightly.
In a large mixing bowl, whisk the eggs, sugar, and vanilla extract until combined. Pour in the melted chocolate mixture and stir until smooth.
Add the flour and cocoa powder to the mixture and gently fold until just combined. Avoid overmixing, as this can make the brownies more cake-like instead of fudgy.
Pour the brownie batter into the prepared tin and spread evenly. Bake for 25–30 minutes, or until the centre is just set and a skewer inserted comes out with a few moist crumbs.
Allow the brownies to cool completely in the tin before decorating. This helps create cleaner slices and prevents toppings from melting
Decorate the cooled brownies with melted chocolate drizzle, Halloween sprinkles, candy eyes, or your favourite spooky toppings. I like to make little ghostie shapes by using the colored chocolate piped onto a sheet of wax paper and use these to decorate too!
Slice into pieces and serve. For neat brownie squares, use a sharp knife and wipe it clean between cuts.
Tip: For the fudgiest texture, avoid overbaking the brownies. They will continue to firm up as they cool.
