1. Put the spring onions, garlic and lemongrass in the bowl of a food processor and pulse until finely chopped. Add the pork and pulse until the meat is also finely chopped. Add the bread, chilli flakes, salt, pepper and egg and mix well.
2. Shape the mixture into walnut-size meatballs and arrange on a plate. Cover with clingfilm and chill in the fridge for at least 30 minutes.