Finely chop the onion and garlic. In a large pan, fry the onion and the garlic in 1 Tbsp of oil for five minutes.
Meanwhile, remove the stalks from the cauliflower and cut into small florets. Chop the aubergine carrot and sweet potato into bite-sized chunks.
Add the remaining oil to the pan, then gently sauté the aubergine, carrot and sweet potato for ten minutes (under cover).
When the vegetables are tender, add the tomato purée and the curry powder & paste. Season with salt and pepper. Stir for a minute or so, then add the cauliflower, pour in the chopped tomatoes and add enough water to cover the vegetables. Put a lid on and cook for another 10-15 minutes.
When the cauliflower is tender, turn off the heat.
Serve warm, with fresh coriander scattered on top.