Combine your coconut milk, chicken stock and fish sauce in a saucepan, and stir to dissolve any lumps. Add the ginger, garlic, sugar and pepper. Stir again. If using fresh lemongrass, chop it into the pan with scissors; if using dried, add the stalks whole. Bring the broth to a gentle simmer over the lowest possible heat while you zest and juice your limes. Reserve a pinch of lime zest, then add the rest to the broth, along with the juice.
Tip the kale and coriander into a colander, and rinse them vigorously (both are horribly good at hiding grit). Use scissors to chop them as finely as you can manage, then set to one side.
Rinse and slice the spring onions, then add most to the broth, reserving a few green shreds for garnish. Rinse, slice and de-seed the chillies, and do the same.
This should all take about 10 minutes, and by this time the house will smell beautiful and bright and green. Rinse the rice, then tip it directly into the broth. Cover the pan and cook for 18 minutes, stirring a couple of times to break up any clumps of rice.
Taste: the rice should be soft and sticky, with broth bubbling all around and over it. Stir through the kale and coriander and cook for two minutes more. Finally, add the prawns and cook for another two minutes.
Decant into bowls: a mound of tender rice, studded with pink prawns and flecks of vivid green, with a moat of richly scented broth. Scatter with the reserved lime zest, loops of red chilli and hoops of green onion. Serve straight away.