Arame is a mild-tasting sea vegetable that is similar to hijiki. Rich in iron, calcium, and other minerals, arame is often cooked with sweet root vegetables and served as a side dish.
Soak Arame for 10 minutes. Rinse well and drain. Rinse mushrooms and remove stems. Place in baking dish. Dice stems and set aside. Place Arame with soaking water in small sauce pan. If necessary add more water to cover. Bring to boil and simmer for 15 minutes.
Drain. Squeeze out liquid from Arame and mince. Heat oil in small pan and saute onion and mushroom stems for 3-5 minutes. Add Arame. Combine Mirin, Shoyu, lemon, and ginger juice.
Pour half over Arame mixture and simmer until liquid evaporates. Stuff mushroom caps with Arame mixture; pour remaining marinade over mushroom caps. Cover and bake at 350 F for 20-25 minutes. Garnish. Be careful not to overcook; mushrooms will shrink.