Finely chop mushrooms by hand, or alternatively, pulse in a food processor until finely chopped. Remove to a bowl. Finely chop garlic, lemongrass, eschalots, ginger and chilli by hand or in the food processor
Combine palm sugar, fish sauce, sweet chilli sauce and lime juice in a bowl.
Cook rice vermicelli noodles following packet directions. Drain, cover and keep warm
Heat a large wok over medium heat until hot. Add oil and garlic mixture, stir-fry until soft and aromatic
Add mushrooms, increase heat to high, stir-fry for 3-5 minutes until moisture has almost evaporated
Add pork mince, stir-fry for 5 minutes until mince is cooked. Add 2 tbs palm sugar mixture and stir-fry for 2 minutes
Pile noodles into bowls or plates. Spoon over mushroom and pork mince. Top with bean sprouts and herbs. Serve drizzled with remaining palm sugar mixture