Add the rice to a large pan with the vegetable stock, bring to the boil and allow to simmer for 30 minutes.
While the rice is cooking, add the onion and the oil to a small, lidded pan and cook gently for at least 10 minutes on a low heat until it softens. If it starts to burn, add a splash of water.
Once the onion has turned translucent and has softened, stir in the turmeric, cumin, Nigella seeds, lemongrass, ground coriander, and ginger. Remove from the heat then add the coconut cream.
Once the rice is properly cooked, add the peas and the onion spice mix to the rice and stir through. Keep the heat on a low setting and allow to heat through for a few minutes.
Turn off the heat and use a hand blender to blitz the soup to your desired consistency. If you like it smooth, continue to blend until it is as smooth as you like it and add a little more water if needed.
Serve immediately and scatter on the extra peas, Nigella seeds, coriander and a squeeze of lime juice.