Cut Nappa cabbage into squares, about 2" in size. Cut Aburaage into 1/2" (1 cm) strips.

In a pot, put Dashi, Soy Sauce, Mirin, and salt, and let boil. Add cabbage, and cook coved at medium heat for 5 minutes. When cabbage is wilted, add Aburaage. Cook for a few minutes, and let cool covered.