Brown-butter cod loin with leeks, spinach and grains

Heat the butter in a heavy-based, non-stick frying pan until foaming. Season the cod and cook on one side over a medium-low heat until golden and almost cooked through (about 8 minutes); turn down the heat if it’s browning too much. Flip and fry for 2-3 minutes more, until cooked. Set aside, covered with foil.

Put the leeks into the pan and cook over a medium heat for 4-5 minutes, until soft and golden. Add the grains and spinach, cooking for 1-2 minutes, until just wilted; season. Add any juices from the rested fish to the grains. Serve with the fish, mustard mayonnaise and some lemon wedges, if liked.