In a bowl, combine the butter and dark chocolate. Melt the mixture in a brain-marie. stirring occasionally until fully melted and smooth.
In a separate bowl, beat the eggs and sugar with an electric mixer until the mixture is pale, thick, and fluffy.
Gently fold the melted chocolate mixture into the egg mixture using a spatula.
Sift in the flour, cocoa powder, and baking powder. Add a pinch of salt and mix until smooth and lump-free.
Line a 24x24cm cake mold with parchment paper. Pour the batter evenly into the mold and smooth the top. Bake in a preheated oven at 180°C/360°F for 30 minutes.
Let the brownies cool completely before cutting them into squares. Plate them up and enjoy every chocolatey bite.
