1Preheat your oven to 180°C (350°F) and line a 20cm (8-inch) square baking tin with parchment paper.
Melt the dark chocolate and unsalted butter together in a heatproof bowl over a pot of simmering water, stirring occasionally until smooth. Remove from heat and let it cool slightly.
In a large mixing bowl, whisk together the granulated sugar and eggs until the mixture is pale and creamy.
Stir in the melted chocolate and butter mixture, followed by the vanilla extract.
Sift in the all-purpose flour, cocoa powder, and salt. Gently fold the dry ingredients into the wet ingredients until just combined.
Pour the brownie batter into the prepared baking tin, spreading it evenly.
Bake in the preheated oven for 25-30 minutes, or until the edges are set and the center is slightly fudgy.
Allow the brownies to cool in the tin before slicing into squares and serving.