Pound the cilantro roots, whole peppercorns and salt to a coarse paste in a granite mortar, about 15 seconds. Heat 1 tablespoon of the vegetable oil in a wok or frying pan over medium-high heat until it shimmers. Decrease the heat to medium and add the onion, Chinese Celery stems, ginger and the cilantro-root paste. Cook, stirring frequently, until the onion has wilted slightly, about 90 seconds. Turn off the heat. Pour the remaining 1 teaspoon of vegetable oil into the clay pot and rub to coat the bottom and sides. Line the bottom of the pot with one layer of the pork belly, then add the onion mixture in an even layer. Use kitchen shears to snip off any pointy feelers from the shrimp, then snip through the shell on the back of the shrimp and barely into the flesh to expose the vein. Discard the veins and add the shrimp to the pot in one layer. Sprinkle on the cracked black pepper. In a medium mixing bowl, toss the noodles with the black soy sauce until the noodles are an even amber color, then add the noodles to the pot in an even layer. You can stop here and cook the dish up to an hour later or cover and keep the pot in the fridge overnight. Let it come to room temperature before cooking.
In a small bowl, stir together the thin soy sauce, oyster sauce, seasoning sauce, Shoaxing wine, sugar, sesame oil and water. Measure 3 tablespoons of this mixture and drizzle it over the noodles. Top with the Chinese celery leaves.
This dish tastes best cooked on a charcoal tao (you can get away with cooking it on a gas stovetop rack). Prepare the tao, as you would a charcoal grill, to cook over medium heat. Cover the pot with the lid and cook until the noodles and the shrimp are completely cooked, 9 to 12 minutes, resisting the temptation to check under the lid until at least 9 minutes have passed. You won't be able to tell until you stir, but the pork belly should be slightly caramelized. If it's not, then use a slightly higher heat the next time you make the dish. Stir well before serving. If you've made it, serve the dipping sauce alongside and occasionally dunk a shrimp.
This recipe was provided by a chef, restaurant or culinary professional. It has not been tested for home use.