Fry the onion in the oil in a large frying pan or saucepan until softened. Stir in the turmeric, then the rice, and keep stirring until the grains are golden.
Pour in the hot stock, bring to the boil, then reduce the heat, cover and cook for 15 mins until the rice is tender.
Remove from the heat and stir through the spring onions, pistachios and some seasoning before serving hot, or allowing to cool.