Rinse the fish in cold water then rub all over with the salt and a lot of black pepper. Leave covered at room temperature for about 30 minutes to draw out the excess moisture and firm up the fish

Put a grill rack into a roasting pan and pour in boiling water to a depth of about 2 1/2 cm.

Bring to a gentle simmer over a low heat

Transfer the fish 2 heatproof serving plate, discarding any liquid which may have collected around it.

Sprinkle on the cumin seeds and ginger, then place the plate onto the rack

Cover the whole roasting pan with foil pressing it round the edges to former close a seal as possible, then cook for about 20 minutes until the fish flakes easily

Test it with the point of a sharp knife near to the gills so as not to spoil the appearance of the fish when serving

Remove the foil take off from the heat and sprinkle over the lemon juice

Quickly heat the oil in a small frying pan, add the garlic and coriander seeds then stir fry over a high heat for about 1 minute, until the aroma of the spices is quite powerful - be careful not to burn over the spices will become bitter

Pour the sizzling oil over the fish then serve at once garnished with thinly sliced spring onions