Melt the butter and chocolate over a Bain Marie and allow cooling for a couple of minutes. Beat eggs and sugar to batter then stir in the melted chocolate and butter.
Beat together then fold in sieved flour and walnuts. Pour into a pre-lined Swiss roll tray. Bake at 180oC / Gas 5.
Meanwhile whip the cream and icing sugar to soft peaks. Mash the majority of the raspberries with a fork keeping some aside for a garnish. Fold them into the cream. The brownie is cooked when you can skewer it and it comes out clean. Remove from the oven and allow to cool.
Slice the brownie and serve with raspberry cream spooned on the side of the brownie.