An old favourite from ” Big Flavours and Rough Edges” by David Eyre and the Eagle Cooks. Its best to use undyed smoked haddock if you can get this. The Horseradish Mash can be replaced with Saffron Mash. Infuse a gram of saffron in the milk( or half milk and cream) while it is heating through and omit the horseradiash.