Put the ginger, garlic, lemongrass, coriander and 1 chilli in a food processor, then pulse until puréed. Heat the oil in a pan over a low heat. Add the purée and cook for 5 mins. Stir in the beef, soy, five-spice, sugar and stock. Put on a lid and bring to the boil, then lower heat and simmer for 1 hr 15 mins. Remove the lid and cook for a further 15 mins until the beef is tender.
Just before serving, prepare noodles following pack instructions. Drain well, then divide between 2 bowls and spoon over the beef stew. Serve sprinkled with the remaining chilli and coriander leaves, with lime wedges for squeezing over.
