thinly sliced spring onions, to garnish (optional)
Heat the oil in a large saucepan and cook the curry paste for 1 minute over a medium-low heat, until aromatic. Pour in the chicken stock, then add the fish sauce, sugar, chilli and lime leaves, if using. Bring to the boil and simmer for 4–5 minutes to allow the flavours to develop.
Meanwhile, bring a large pan of water to the boil. Add the noodles, then turn off the heat and set aside for 3 minutes, until tender. Alternatively, cook according to the packet instructions. Drain well, then divide the noodles between 4 bowls. Top with the shredded chicken, then ladle over the hot broth. Garnish with spring onions to serve, if desired.