Wash the rice and keep aside. Boil 3 to 3.5 cups water in a heavy-bottomed sauce pan. Add the rice when water boils and simmer for 7-10 minutes, till the rice is completely cooked.
Add milk and continue to simmer for another 25-30 minutes, till the milk is reduced to half.
Add the brown sugar and crushed cardamom and edible camphor. Simmer for 5 minutes.
Heat ghee in a pan and fry the cashews and raisins. Pour it into the payasam. This step is optional
Serve hot, warm or chilled.