Mince the shallot, garlic and lemongrass very fine. Mix the sugar, pepper, soy sauce, fish sauce and cooking oil to obtain the marinade.
Cut the pork into bite-sized pieces and marinate for at least 30 minutes in the fridge, more if possible.
Preheat oven to 200°C. Get the pork out of the fridge and to room temperature.
Bake the pork in ovenproof dish for 20-30 minutes, until thoroughly cooked. Then turn the oven to broil/grill setting and grill on both sides until the meat is nicely browned. (alternatively, grill the meat until cooked).
Boil enough water to cover the rice vermicelli, and pour over them. Leave to cook for 2 minutes, then drain and leave to cool.
Wash the salad and the soy. Dry the soy well. Crush the peanuts into little fragments with a mortar and pestle.
In each bowl, put: a quarter of the rice noodles, a quarter of the salad, and a quarter of the soy. Then add the pork, mint and roasted peanuts.
Serve with nuoc cham, and let each guest mix their salad!
Recipe by Aliette de Bodard at https://www.aliettedebodard.com/recipes/bun-thit-nuong-barbecued-pork-rice-noodles/