Cook the pork belly with ginger, star anise and bay leaves in a wok. Transfer cooked pork belly in a bowl. Pour 2 tablespoons of dark soy sauce and marinate it for 10 minutes.

Use a toothpick to drill holes in pork skin and drain water. Heat a wok with oil, and stir-fry the pork belly until golden.

Add 1 tablespoon of pepper, 1/2 tablespoon of sugar, 2 tablespoons of light soy sauce and 2 tablespoons of beer in a bowl.

Cut the pork belly into slices. (keep the bottom glued together)Put it in a steaming bowl and pour 1/2 bowl of sauce mixture on it. Spread a layer of sauce on the surface of pork belly and place pigskin side down.

Cut the dried preserved mustard greens into sections. Heat a wok with oil again, and stir-fry the dried preserved mustard greens well. Add the rest of the sauce in the wok.

Transfer the dried preserved mustard greens in the steaming bowl. Steam them in a steamer for about an hour. Serve it.