Preheat the oven to 180oC/350oF/Gas
4. Grease then line a 20cm square cake tin with greaseproof paper.
Melt the butter in a pan and stir in
the cocoa powder. Set aside to cool.
Beat together the eggs, sugar and
vanilla essence in a bowl, then stir in the cooled cocoa mixture with
Sift over the flour and fold into the
mixture with a metal spoon.
Pour the mixture into the cake tin and
bake in the oven for 30-35 minutes, until risen. Remove from the oven
(the mixture will still be quite soft and wet, but it cooks further
while cooling) and leave to cool in the tin.
To make the frosting, melt the
chocolate and butter together in a pan and remove from the heat. Beat in
the soured cream until smooth and glossy.
Leave to cool slightly, and then
spread over the top of the brownies. When set, cut into 12 pieces.