Red cabbage or red cabbage 2
In red cabbage, you can "control" the color by adding either a fruit acid or vinegar when heated or boiled. In this case, the cabbage is beautiful red. But if you add a little bit of flavoring (health food), the whole takes on a rather blue color and the acidity is reduced significantly!
With the addition of soda, you should make sure that this also shorten the cooking time somewhat (cooking water is softened by soda and also more alkaline). The soda should be added knife-edge way.
