Preheat the oven to 180C/350F/Gas 4.
Heat the olive oil in a frying pan, add the onion and chilli and fry for 1-2 minutes, or until softened. Add the ground turmeric, salt and freshly ground black pepper and fry for another minute.
Spoon the onions and chilli mixture into a deep ovenproof dish, add the rice, pour over the stock and stir well. Cover with aluminium foil and place into the oven to bake for ten minutes, or until all the water has been absorbed into the rice and the rice is tender.
Blanch the peas in a pan of boiling salted water for 2-3 minutes, then drain and add to the rice along with the butter. Stir until the butter is melted and the mixture is well combined.
Grate the root ginger into a clean tea towel and then squeeze the ginger juice into the rice. Discard the ginger flesh. Stir well.
To serve, spoon the pilaf onto a serving plate.