Gratin of Cod with Vegetables

This is based on a Norwegian dish from the port of Trondheim, right on the Arctic Circle, which is frozen in for the whole of the winter. It was given to me by a client of mine for whom I managed to get an expedited divorce, otherwise she couldn’t have married her new husband because she couldn’t have got into his village north of Trondheim once the ice had come. It’s a dish designed for cod, but you can use haddock, ling or grey mullet for it. Or indeed any firm, white fish.