Preheat oven to 180 C / Gas 4. Grease a springform tin and sprinkle the bottom and the sides with a thin layer of breadcrumbs.
In a large bowl, cream together the butter and sugar. Add one egg at a time stirring well after each addition. Fold in the melted chocolate and vanilla extract. Mix well.
In a second bowl mix together flour, cornflour, cocoa and baking powder. Alternate adding the flour mixture and the milk to the egg mixture and stir well. Finally add in the rum and fold the berries into the cake mixture.
Pour cake mixture into the prepared cake tin and smooth the top.
Bake for 55 to 60 minutes in the preheated oven until a skewer comes out clean. Remove from the oven and set on a cooling rack. Pour the orange juice over the hot cake and let cool.
To serve, dust with icing sugar.
This recipe calls for mixed berries of your choice. In this recipe, berries such as cherries, raspberries, blackberries and strawberries work great.