Planked Bluefish with Lemon Mustard

Bluefish is a dark, rich, oily fish that is ineffably delicious when caught and eaten the same day and less good when any less fresh than that. If you live in a coastal community in the East (Nantucket, Martha’s Vineyard, Cape Cod, or the Jersey Shore, for example), you’re in business—make friends with a local fisherman. If not, the same recipe can be prepared with wild salmon.