Cattelin was one of the best and cheapest restaurants in Stockholm. It had survived wars, disasters and changing tastes, and still managed to pack ‘em in until they were forced to shut down in 2011, so they must have done a lot of things right.
This is a nice dish for a lunch party – it is not too time-consuming to make either. The fish you use should be firm. An admonishing word along the way: Make sure the mushrooms are browned properly, not boiled.