Grilled Swordfish with Clams and Broth-Like Miso Sauce

Miso provides a simple and savory addition to the cooking liquid from fish and shellfish. Keep in mind, however, that miso is very salty, so it must be used sparingly, especially with the salty cooking liquid from clams or mussels. This technique—surrounding grilled seafood with miso- and shellfish-scented broth—can be used with any firm-fleshed fish. Shiso or kinome leaves are typical Japanese garnitures, but tiny watercress or mint sprigs will also work. The swordfish steaks may also be g