Wash and cut the tomatoes in halves. Add water, ginger, garlic, green chilly, onions Ca-shewnuts, deggi mirch and put on medium fire. Add all the whole spices. Cook till tomatoes are mashy. Remove, puree and strain them.
Boil potatoes in enough water and keep aside.
Heat a handi and add oil. Add mustard seeds and once they crackle add heeng, sauteand then add curry leaves. Add potatoes and chopped raw mango. Sautethem and add turmer-ic, coriander powder and saute.
Then add the tomato curry and cook for 2 minutes. Add mango juice and salt, get it to a thick consistency. Sprinkle with chopped green coriander and serve hot.