Use this kombu (seaweed) and shiitake mushroom dashi (or stock) in soups, stews, and hot pots — and for cooking rice, too. After the overnight infusion, the kombu and shiitake can be added to the water for a hot pot. When heated together with the other ingredients in the hot pot, the kombu and shiitake make for an even richer dashi. The shiitake also can be sliced (discard the stem) and cooked in a vegetable soup.