Soak the sago in enough water for 30 minutes. Drain and set aside. Boil the milk and keep it ready.
In a heavy bottomed vessel, heat 1 tsp ghee and add the cashews. Fry the cashews till golden and set aside. Add the raisins and fry till they puff up. Set aside.
Add the remaining ghee and sago. Fry for 2 minutes. Then add water and 1 cup milk and cook till the sago turns transparent and soft.
Add the remaining milk and bring to boil. Turn the heat to medium and add the sugar. Mix well till the sugar dissolves completely.
Add the cardamom powder and cook till the payasam thickens to your desired consistency. Garnish with fried cashews and raisins.
Notes
Depending on the variety of sago, the soaking times may vary. Mine was small, so I soaked for 30 minutes only.
Frying the sago avoids the sago clumping together while cooking.
The payasam thickens as it sits, keep extra ½ cup boiled milk ready to add if the payasam is too thick while serving.