Don't throw away the scallop skirts surrounding the nut of meat once you have cleaned them, as they are great used to flavour a broth like this, or even deep-fried afterwards. If you're not a dab hand with a knife then ask your fishmonger to clean your scallops for you and reserve the skirts.
You can buy seaweed in Asian supermarkets, as well as seaweed salad mixes which are ideal for garnishing soups like this. Dashi is a soup or stock base that is made from dried kombu or kelp and dried bonito flakes and can bought in instant form; or you can simmer bonito flakes and kombu in water until the stock reaches the correct strength.
4 medium scallops, cleaned, with the roe and skirt reserved
1.5ltrs dashi (instant or fresh)
Sea salt and freshly ground white pepper
10g mixed seaweed for salad
4 spring onions, trimmed and finely shredded on the angle
Put the scallop skirts in a saucepan with the dashi, bring to the boil and simmer for 30 minutes, then remove from the heat and strain through a fine meshed sieve into a clean saucepan.
Add the dry seaweed salad mix to the strained soup and leave for 5-10 minutes. To serve, bring the soup to the boil, adding the spring onions and the roe, then cut each scallop into 4 thin slices and place in the bottom of 4 warmed soup bowls and pour the soup over.