The cabbage you are talking about sounds like pointed white cabbage or spring cabbage.
It needs only to boil for a couple of minutes and then simmer for about five more minutes.
Make a white sauce from the water, or some of it, and pop the strained cabbage into it.
Ordinary white cabbage (winter cabbage) should be covered in water , salted and boiled for about 20 mintues.
Red cabbage should be shredded finely, put into very little water, about and inch in the bottom of the pan, salted and cooked for 30 minutes. You can add a peeled, cored and finely sliced cooking apple if you like.
Once the cabbage is tender add sugar and vinegar to taste.