Put the rice in a bowl and wash thoroughly. Once the water starts to run clear, fill the bowl with cold water and soak the rice for 30 minutes, then drain using a fine sieve. In a small jug, measure out the stock or water and mix with the soy sauce.
Meanwhile, put the coriander and cumin seeds, peppercorns and fenugreek in a small pan and toast over a low heat for a minute or so. Grind them to a fine powder using a spice grinder or pestle and mortar. Stir in the chilli powder and turmeric.
Heat the vegetable oil in a heavy-based lidded saucepan over a low heat. Add the onion and a good pinch of salt, then cook gently for 10-15 minutes, stirring frequently, until browned. Add a tiny splash of water if you feel they are cooking too fast.
Melt in the butter, stir in the garlic and the spice mix and cook for 1-2 minutes, then add the tomatoes, sugar and salt. Cook for 5 minutes. Stir in the drained rice and the stock mixture. Put on the lid and simmer for 10 minutes over a low-medium heat, then turn the heat down as low as it can go. Add the peas, return the lid to the pan and cook for a further 8 minutes to steam. Turn off the heat and let it sit for 10 minutes with the lid firmly left on.
Carefully open the lid and give it a gentle stir with a rice paddle or wooden spoon to mix it all up – you should notice a slightly crunchy crust at the bottom of the pan. Divide the rice among bowls and scatter with chives.
