In a blender, combine onion, tomato, tomato paste, cashews nuts, cumin seeds, ginger, garlic and water. Blend it into a thick smooth paste.
Heat oil in a kadhai or nonstick pan and add cinnamon powder and cardamom powder. Immediately spoon out the onion tomato masala into it and saute for about 15 minutes sauteing it at interval of every 2 minutes at medium – high flame or until the masala starts to dry up.
Add chili powder, turmeric and coriander powder. Saute for another 5 minutes at medium flame.
Now, lower the flame and add coconut milk, salt,sugar, garam masala and kasoori methi. Mix until the masala dissolves well into the milk and there are no lumps. Cover and cook for about 15 minutes at low-medium flame. Make sure the milk does not curdle so keep the flame low and stir at interval of 5 minutes.
Once done, remove the lid and place the koftas into the gravy. Turn it off and garish with cilantro and serve with naan and jeera rice/steamed rice.