Put the block of pork belly into a small pot. Fill with water just enough to cover the meat. Add scallions and ginger. Bring the water to a boil then turn the heat down to the lowest. Cover with a lid and leave to simmer for 45 minutes.
Turn off the heat. Let the meat sit in the pot for a further 30 minutes then take it out. While still hot, rub a good layer of dark soy sauce over the skin to darken it. Leave it to cool completely.
Then cut the pork into slices (about ¼ inch/0.7cm thick). Put them into a bowl, along with dark soy sauce, light soy sauce, oyster sauce, Shaoxing rice wine, sugar and white pepper. Leave to marinate for 1 hour or overnight.
Prepare the Mei Cai
Rinse Mei Cai very well under running water to remove surface salt and any dirt. Then leave it to soak in water for 1 hour. Taste a bit to check the saltiness. Extend the soaking time if it’s too salty. Rinse again then squeeze out as much water as possible. Chop it into small pieces.
Heat oil in a wok/skillet. Briefly fry minced garlic, ginger, star anise, cinnamon and dried chili (if using). Add the chopped Mei Cai, along with dark soy sauce, sugar, white pepper, sesame oil and a cup of water (or stock).
Cover and braise for about 5 minutes before you taste the saltiness. Add a little light soy sauce if necessary (it’s fine to be a little on the salty side at this stage).
Steam the dish
In a large deep bowl, place the pork belly slices one by one in a domino pattern, with the skin facing down. Fill the sides with a few pieces too. Put any remaining pieces over (and the marinade too). Top the bowl with the braised Mei Cai, along with all the liquid.
Put the bowl into a steamer basket (or over a steamer rack). Bring the water in the pot/wok to a full boil then turn the heat to medium-low. Leave to steam for 2 hours. Make sure to check the water level every half an hour and top up when necessary.
Carefully take the bowl out. Cover it tightly with a serving plate. Hold the bowl against the plate tightly (using protective gloves to avoid burning) then quickly flip over so that the content in the bowl lands on the plate. Serve warm with steamed rice.
Make ahead
Prepare a big batch of pork belly (simmered & marinated) and Mei Cai (braised) at a time. Freeze them in portions. Defrost then assemble and steam a bowlful any time you wish.
Notes
1. You can use either ready-to-eat Mei Cai or dried Mei Cai. Both require soaking to either reduce the saltiness or rehydrate the vegetable.2. Since different Mei Cai come with various levels of saltiness, it’s important to taste before adding any light soy sauce.