Bring about 2 inches of water to a boil over high in a large pot, and add the pork belly. Add more water to cover the pork, if necessary, then boil for 3 minutes. (This step removes impurities from the pork.) Drain and set the pork aside. When cool enough to handle, cut the pork into 1 ½-inch cubes and pat dry with a paper towel.

Heat the oil in a well-seasoned wok (or large heavy-bottomed pot with high sides) on low, until wisps of smoke curl up off the edges. Add the 2 tablespoons crushed rock sugar and stir until the sugar melts and dissolves.

Adjust the heat to medium. Working in batches if necessary, and being mindful of the residual water popping in the oil (use a splatter screen if you have one), gently add the chunks of pork belly. Cook, undisturbed, allowing the pork to caramelize and brown, 3 to 5 minutes per side. (This step gives it a rich caramel flavor.) Add the dark soy sauce, stir to combine and cook for an additional minute.

Add the stock, light soy sauce, Shaoxing wine, remaining 2 tablespoons whole rock sugar, the star anise, ginger and scallion segments. The mixture should come three-quarters of the way up the side of the pile of pork. If not, add more stock or water.

Bring to a boil over high, then reduce the heat to maintain a simmer and cook, partially covered (use a sheet pan or aluminum foil if you don’t have a lid) for at least 3 hours, stirring occasionally to prevent sticking. Add more stock or water as needed; the wok should never be dry. The longer the pork simmers, the more tender and flavorful it will be; it’s ready when it’s soft enough to slip a chopstick in with ease, but you can go up to 2 hours longer to build the flavor even more. When there’s approximately 2 hours of braising time left, add the hard-boiled eggs to the wok, if using. Twenty minutes before you’re ready to serve, add the frozen tofu knots, if using.

When ready to serve, remove the lid, increase the heat to high, and boil until the cooking liquid becomes a thick, dark, glistening sauce that blankets the pork belly. If the pork belly has begun to break down (the lean meat is separating from the fatty portion), use a slotted spoon to remove the pork before cooking down the sauce, and add the pork back in at the end.

Top with the chopped scallions and serve with rice.