This recipe, which I got from a South African Gujarati family, is not really a soup but rather a sweet and sour soupy dish called fajeto. It is normally served with meals in small bowls and eaten with the fried puffy breads called pooris, but I strain out all the leaves and seeds that would normally float in it and serve it as a soup. My friends and family love it. It needs to be served hot, as it is thickened with very nutritious chickpea flour that does not behave well when it is cold. It is very quick and easy to make, since it uses canned mango puree. One of India’s finest mangoes is the Alphonso, and it is canned Alphonso puree that you should look for. All Indian grocers carry it. The brand I like and use is Ratna. It comes slightly sweetened. Conveniently, the 30-ounce Ratna cans hold exactly 3 cups, just what you need here.