Break boiled potatoes in small pieces with hands and keep it aside. Make tomato puree in mixer and keep it aside.
Heat the kadai/wok at medium heat and add dry red chilly, hing, kasoori methi, cumin seeds and grated ginger.
Mix them well and cook for few seconds. Be careful do not burn them. Now add turmeric powder and Kashmiri lal mirch powder and mix them well.
Now add tomato puree, salt, mix everything and cook till oil is separated from tomatoes.It may take 5-6 minutes, keep stirring after every few minutes to avoid burning.
Once oil is separated add cumin powder, red chilly powder and coriander powder and mix them.
Add potatoes, saute well and cook them with masala for 3-4 minutes. Now add 1 cup of water, mix and cook again for 3-4 minutes.
Aloo tamatar ki sabji is ready to serve.Garnish it with some fine chopped coriander leaves.