Directions

1. Preheat the oven to 190°C/375°F/Gas 5 and grease and line two 20cm (8in) Victoria sandwich cake tins. In a heatproof bowl, break 50g (2oz) of the chocolate, and place over a pan of gently simmering water to melt.
   In another bowl, beat together the butter and brown sugar until pale. Beat in the melted chocolate and mashed potato.
   Gradually beat in the eggs, adding a little of the flour with each. Sift the remaining flour and salt into the mixture and add the milk. Gently fold together until well combined.
   Divide the mixture equally between the prepared tins and smooth over the tops. Bake for about 25 minutes until risen and springy-firm to the touch. Turn onto wire racks to cool completely.
   Melt the remaining chocolate as above and cool for 10 minutes. Add the cream, the icing sugar and the whisky. Carefully whisk together until thick and creamy. Spread the jam over one half of the cake and then spread half the chocolate cream on top. Sandwich together with the other half. Spread the remaining chocolate cream on top. Decorate with fresh raspberries before serving.