This dish gets a lot of its flavour from belacan - salted, fermented shrimp paste. It has a very strong smell that some people find unpleasant, but it's essential to many Asian cuisines. There are different types of belacan: some are like a soft, spoonable paste that is sold in jars, but for this dish, buy the dried shrimp paste that comes in a small, hard block. When mixed with other ingredients, the pungency and strong flavour are muted, and the belacan adds a rich umami to the dish.
Cloud ear mushrooms, also called cloud ear fungus, are most easily available dried. They're small and light, but grow enormously when soaked. You can substitute the similar wood ear mushrooms.
Serve these noodles with fresh lime juice and sambal belacan - chilli shrimp paste, which you can either buy (it comes in jars) or make yourself.
Put the rice vermicelli in a wide bowl, add warm water to cover and leave to soak for about 30 minutes, or until pliable.
Briefly rinse the cloud ear mushrooms then put them in a separate bowl, add warm water to cover, and leave until fully hyrated, about 15 minutes.
While the vermicelli and cloud ear mushrooms are soaking, prepare the other ingredients. Cut the pork belly into strips about 1cm (7/16 in) wide and 3mm (⅛ in) thick.
Put the pork belly in a bowl and add the soy sauce, rice wine, sugar, white pepper, cornstarch and tsp salt. Combine thoroughly then set aside at room temperature.
Remove the heads, shells and tails from the shrimp (save them to make shrimp stock or shrimp oil for another dish.) Cut the shrimp into 1cm (7/16 in) pieces.
Crumble the belacan into small pieces. Halve the onion then thinly slices. Cut the carrot and bell pepper into thin matchsticks. Cut the bird's-eye chilli or chillies into thin rounds, shaking out and discarding the seeds as you go. Julienne the spring onions into 4cm long (1½ in) pieces.
Squeeze the excess water out of the mushrooms and trim off the hard stem (if there is one). Cut the mushrooms into thin strips.
Drain the rice vermicelli in a colander.
Heat a wok over a high flame then add about 20ml (4 tsp) of cooking oil. Swirl the wok to coat it with the oil. When the oil is hot, add the pork belly and cook until lightly browned, stirring as necessary. Add the shrimp and stir-fry until the pieces turn pink, then scoop the pork and shrimp from the wok and put into a bowl.
Place the wok (no need to wash it) back over the flame and add 15ml (1 tbsp) oil. Swirl the wok to coat it with the oil, then add the onion and stir-fry for about 30 seconds, or until slightly wilted. Add the carrot, bell pepper and mushrooms and stir-fry for about 30 seconds, then put the vegetables in the bowl with the pork belly and shrimp.
Place the wok (again, no need to wash it) back over the flame and add 10ml (2 tsp) oil. When the oil is hot, add the belacan and press on it with the wok-spatula to mash it to a paste. Add the bird's-eye chilli and stir fry for about 15 seconds.
Add the rice vermicelli and mix thoroughly, using long chopsticks to lift and stir them so they don't break up.
Put the pork belly, shrimp and vegetables back into the wok, season lightly with salt then mix well.
Drizzle about 60ml (¼ cup) of water into the wok. Cover with the lid, lower the heat and simmer, stirring occasionally, until the liquid is absorbed and the vermicelli is tender but not mushy. Iif necessary, add more water.
Taste for seasonings then stir in the spring onion and coriander. Serve with lime wedges and sambal belacan.