Found from Plantanswers.com "Our present strain was derived from a Savoy (crinkled) cabbage type."
Napa
The broadest.
So they can photosynthesise ie make food
You needn't to remove leaves. Just cut the whole cabbage as you were cutting an apple, on only one piece. one for each person. Cooking the pieces in a pressure cooker make them soft, and you can cut...
put some vinegar on it and wait for at least two hours