Make thin slices of the swiss roll cake and place half of it at the bottom of the dish.
Blend all the ingredients for the custard layer in a blender for 1-2 minutes.
Pour half of this mixture over the cake layer.
On top of the custard mixture, again layer with the remaining sliced swiss roll.
Pour the remaining custard mixture.
Make the chocolate sauce
Whisk up all the ingredients for chocolate sauce, till you get a smooth texture. Pour this on top of the prepared pudding and spread it evenly.
Refrigerate for 5-6 hours or preferably overnight.