• 1½ lb / 680 g skinned fish fillets
• salt
• freshly ground black pepper

Dry the fillets thoroughly and cut into four pieces. Season lightly on both sides with salt, pepper and lemon juice. Prepare the lettuce leaves by draping them over a large colander, and gently pouring boiling water over them to blanch them. Cool under cold running water, and dry carefully on kitchen paper. Cut out any central ribs that still remain firm and that would make it difficult to roll