Heat a large pan, fry the curry paste until fragrant, add the lamb, then brown on all sides. Pour in the rice and stock, then stir well. Bring to the boil, cover with a lid, then cook for 15 mins on a medium heat until the rice is tender.
Stir through the spinach, put the lid back on the pan and leave to steam, undisturbed, for 5 mins before serving.