Bring a pot of salted water to the boil and add your cauliflower. Bring back to the boil for 1 minute, then remove the florets with a slotted spoon and leave in a colander. Keep the cauliflower water to one side.
Heat a wide pan big enough to hold all the ingredients at once. Add a good splash of vegetable oil and when it’s hot, add the mustard seeds, the asafoetida, the curry leaves and turmeric. Fry for a few seconds then add the diced potatoes, just enough of the cauliflower water to cover them and some salt. Cover with a lid and simmer gently until the potatoes are just cooked. Add the peas, chillies and cauliflower florets, stir and replace the lid. Cook over a gentle heat until everything is cooked and soft, and the liquid has reduced. Taste and season well with salt and pepper, sprinkle with loads of chopped coriander and some coconut shavings and serve.