I have been cooking mustard greens(tsunga) the way my mother taught me. That is, boil it until all the color is gone and the green looks more grey. I know I am not the only one. Good thing is I have found a way to cook mustard greens and they still maintain their colour and retain most of the nutrients. There is no guarantee though that my mother would want to try these by just looking at them because she is so used to mustard greens loosing their colour. I definitely know that my grandmother would not even dare try.