Grease and line a swiss roll tin with greaseproof paper.
In a large bowl over some simmering water, melt the butter
and the chocolate then mix until smooth OR place the butter
and the chocolate into a glass bowl and give it three 60
second shots in the microwave at around level 600, mixing
In a separate bowl, mix together the cocoa powder, flour,
baking powder and sugar, then add this to the chocolate
mixture and stir together well.
Beat the eggs and fold them in gently to achieve a silky
Pour the brownie mix into the baking tray and place it in
the oven for around 25 minutes. You don't want to
overcook them, so, unlike cakes, you don't want a skewer to
come out all clean. The brownie mixture should just
barely move when you shake the tray. They will come out
slightly springy on the outside but still gooey in the middle.
Allow to cool in the tray, then carefully transfer to a
large chopping board and cut into chunky squares.