Schnapper Steamed in Seaweed, Sea Urchin Sauce

• 1 schnapper, weighing 3-4 kg (or 2 weighing 1.5-2-kg)
• salt

Check the schnapper to make sure there are no scales, wash under cold water and pat dry with a teatowel. Season with salt and pepper and place the onion, thyme, parsley and lemon in the stomach cavity. Place the schnapper in a steamer surrounded by the seaweed. Steam the fish for 25-30 minutes — test to see if it is cooked by trying to lift the fillet from the fish near the dorsal fin.