Preheat the oven to 120°C and line a roasting tray.
Slice pork skin into 2.5cm pieces and roast for 2.5 hours until dry.
Boil pork bones in 1 liter of water, discard liquid, and refill to simmer again.
Char onion, lemongrass, shallot, and ginger on a griddle before adding to the broth.
Blend garlic, ginger, lemongrass, and shallots to marinade the pork for 30 minutes.
Brown the pork in rapeseed oil, add marinade, and braise for 40 minutes.
Blanch beansprouts and cook rice noodles in boiling water for 8 minutes.
Deep-fry the roasted pork skin at 180°C until golden brown.
Combine the bone broth with the braising liquid in the wok and boil.
Assemble bowls with lettuce, noodles, broth, sliced pork, aromatics, and fried skin.