Heat a large deep lidded wok, add oil, and stir fry shallots for one minute.
Add curry paste and stir fry for another minute.
Pour in coconut milk and bring to a boil.
Add fish sauce, chicken, potatoes, and aubergines, then return to a simmer.
Cover and simmer gently for 15-20 minutes until chicken is cooked and potatoes are tender.
Stir in lime juice and season with salt and pepper.
Place rice and crushed lemongrass in a saucepan and cover with 500ml of cold water.
Cover, bring to a boil, then simmer for 12-15 minutes until liquid is absorbed.
Discard the lemongrass stalk.
Serve the curry over the rice and garnish with fresh coriander.