Item used | φ174 direct fire bowl material conger eel soy sauce Japanese sake sweet sake sugar watercress balsamic vinegar salt and pepper black pepper cooking point Cooking time about 35 minutes Boil the conger eel in a mixture of soy sauce, sake, mirin, and sugar for about 30 minutes, then remove only the conger eel. Add balsamic vinegar to the remaining seasoning and boil down to ⅓. Add torn watercress, olive oil, salt and pepper, and boiled conger eel and mix lightly. Finally, sprinkle with balsamic vinegar and sprinkle with coarsely crushed black pepper.