Grilled Herring or Mackerel with Mustard

• 1 herring or mackerel
• English mustard or French mustard
• a little butter

Have the fish cleaned and opened out flat like a kipper. Smear both sides fairly generously with mustard. Put a little butter in the grill pan, after removing the rack. Heat gently and, when it begins to sizzle, put the fish in, skin side up. Immediately turn the fish over and continue cooking for about 5 minutes. It will not need to be turned again.

A squeeze of lemon juice heightens t