River Cottage

1. First, combine the mayonnaise, capers and parsley, adding a squeeze of lemon juice too, if you have any. Set aside while you cook the fish. Heat the butter and oil in a non-stick frying pan over a medium heat.

2. Put the flour on a plate and season it well. Dust the fish with the seasoned flour, shaking off the excess, and fry for about 2 minutes on each side (if you are leaving the skin on, fry it skin-side down first for about 3 minutes, then give it a minute on the other side to cook through).

3. Slice the bap in half and butter it generously. Lay a few lettuce leaves on the bottom half and put the fish on top, seasoning it further, if you like, with lemon juice and/or Tabasco. Dollop on the mayonnaise and/or a bit of ketchup if you prefer, then close the bap and eat right away, while the fish is still warm.