Method
Cut the onion into small dice, then place a large, shallow pan or frying pan over a medium heat, and add the oil. When hot, add all the seeds and cook for 1-2 minutes, stirring, until the seeds start to pop, then tip in the onion and lower the heat slightly. Cook the onion gently for about 10 minutes, stirring every now and then, until it is soft and translucent but not caramelised. While the onion cooks, remove any leaves from the cauliflower, then break it into smaller florets and put them into the bowl of a food processor and pulse until you have small pieces roughly the same size as grains of rice (you may need to do this in batches – be careful not to blend too much, or you’ll end up with a paste). Next, crush the garlic into the pan with the cooked onions and season with plenty of salt and pepper, then stir in the garam masala and cook for a couple of minutes. Now tip the prepared cauliflower into the pan and turn the heat up to high. Cook for about 10 minutes, using a fish slice to lift and turn everything regularly – you want the cauliflower grains to catch slightly on the bottom of the pan, so that they brown (this makes them taste great), but try not to let them burn. When the cauliflower rice is mostly golden brown, check you are happy with the seasoning and adjust if wished, then transfer the rice to a serving dish, scatter over the coriander and serve.