Slice the pork into ⅛-inch/3mm thick pieces. Too thin, and it will actually dry out in the soup. Combine the pork with the water, oil, Shaoxing wine, light soy sauce, cornstarch, salt, and white pepper powder. Mix well until the meat has absorbed all the liquid, and let it marinate while you prepare the rest of the ingredients.

Wash the mustard greens clean. (Check out our post on how to wash vegetables.) Shake off the excess water, and cut into bite-size pieces, keeping the leaf and stem pieces separate. Set aside.

Heat a wok or soup pot over medium-high heat. I like to use my wok, because water boils so quickly in it. Over medium-high heat, add 2 tablespoons of oil and the ginger. Let it cook for a minute, then add the mustard green stems, and cook for another minute.

Add the chicken stock and water. Bring to a boil. Add the pork and tofu, stirring to separate the pork pieces. Cover and cook for 8-10 minutes over medium-high heat. Add the mustard green leaves and salt to taste. Cook for another 1-2 minutes. Serve!