Haddock is an underrated fish but, like cod, at its freshest it’s great. Ask your fishmonger to fillet it, remove the scales and pin bones (the single bones running down the centre of the fillet) and cut it into 200 g portions.
To make the Tabbouleh, mix together the spring onion, chilli, tomatoes, couscous, juice of 2 lemons, olive oil, seasoning and boiling water. Cover with cling-film and leave the bowl to stand for 1 hour. Then stir in the parsley, mint and crabmeat.
Cut each lemon segment into three and mix with the olive oil, juice of 1 lemon and season to taste.
Lightly season the haddock portio