Soak soya chunks in salted hot water for 15 minutes. Drain and squeeze out water. Heat oil, add masala paste. Saute on medium heat till oil seperates. Add turmeric powder, chilli powder and coriander, cuminseed powder. Also mix garam masala. Saute for a minute. Add 2 cups water and allow it to boil. Add and mix soya chunks, corn, mushrooms and salt to taste. Boil the curry for 5 minutes. Mix gram flour to thicken the gravy. Serve hot with steamed rice.