Place the pork belly in large pot of water, enough to cover the pork and let it boil for about 5 minutes. Turn off the heat and discard the water and rinse the pork with cold water. Use a fork to prick the skin of the pork belly all over. Place the pork belly in a plastic bag with zip and pour and rub the marinade all over the pork. Push out the air from the bag and zip to seal and let it marinade overnight
On the day of serving:
Preheat about 2 inches of oil in a wok or large pan. Remove the pork belly from the plastic bag and use an absorbent kitchen towel to dab the meat dry with it. Keep the marinating juice. Gently place the pork belly, skin side down, in the oil and let it fry until golden brown and then turn to the other side and fry until golden brown. Remove and set aside.
Fry the yam in the oil until lightly golden brown. Remove to absorbent paper towel. Slice the pork belly, about the same size with the taro, 1/2-inch thickness.
Use a loaf pan or any rectangle dish and arrange the slices of pork belly alternating with the taro slices in the loaf pan. Get the water in the steamer ready
In a medium-size wok or pan, preheat about 1 Tbsp of cooking oil. Stir fry the shallots and garlic until fragrant, about 2 minutes or so. Add the red fermented bean curd, soy bean paste, sugar, and the marinating juice you save from above. Cook for about 2 minutes and then pour this on top of the pork belly and taro slices you assemble in the loaf pan. Steam this for the next 3 hours or until the pork belly is really tender. You may need to replenish the water in the steamer during that 3 hours
After 3 hours, very gently transfer the pork and taro slices into serving platter or you can wait until it's cool down a little bit and gently invert the pan into a serving platter. Garnish with few sprigs of cilantro leaves and ready to serve
You can try not to fry the taro, but they are easier to break after you steam them.
Hakka Kau Yuk (Pork Belly and Taro) https://whattocooktoday.com/hakka-kau-yuk-pork-belly-taro.html