This is a typical Keralan curry, lighter in flavour and fresher than a North Indian curry, and quicker to make because of it. This is a great base sauce to which you can add many different vegetables: try aubergines, okra, spinach, broccoli, peas, mushrooms, chickpeas, green beans and pumpkin or squash. If you like fruity curries, some pineapple, peppers and peanuts would also be lovely (you will need to use less tamarind and perhaps add a pinch of sugar). Here I have used sweet potatoes, chickpeas and seasonal greens. Serve with rice, naan or parathas.