Trim the spring onions and cut three of them into 2½in (6cm) lengths, then into fine slivers. Wash and peel the ginger, keeping the thick peel and any knobbly bits for the marinade. Cut the peeled part into long, thin slivers.

Rinse the fish in cold water and pat it dry. Starting at the head, make three or four parallel, diagonal cuts on each side of the fish, cutting into the thickest part of the flesh near the backbone. Rub it inside and out with a little salt and the Shaoxing wine. Smack the ginger remnants and one of the remaining spring onions with the side of a cleaver or a rolling pin to release their fragrances and place them in the belly cavity of the fish. Leave to marinate for 10–15 minutes

Pour off any liquid that has emerged from the fish and pat it dry. Tear the last spring onion into two or three pieces and lay it in the centre of the steaming plate. Lay the fish over the spring onion (the onion will raise the fish slightly so steam can move around it).

Steam the fish over high heat for 10–12 minutes, until just cooked. Test it by poking a chopstick into the thickest part of the flesh, just behind the head; the flesh should flake away easily from the backbone. When the fish is nearly done, dilute the soy sauce with 2 tbsp hot water.

Remove the fish from the steamer and transfer carefully to a serving dish. Pour the diluted soy sauce all around the fish and serve immediately.