Chop pineapple pieces finely. Keep aside.
Heat 1 tbsp coconut oil or pure ghee in a pan. Add cashew nuts, stir and roast them in ghee till they become golden. Remove and keep aside. To the same pan, then add raisins. As soon as you add them, they will begin to swell and puff up. Stir and cook them till they become plump. Remove and keep aside.
Boil the soaked sago or Sabudana in one cup of hot water till it turns translucent. Keep it aside.
Now in the same pan, add the chopped pineapple. Stir well and saute for 5 minutes on a low flame.
Then add jaggery. Let the jaggery melt. Now add ΒΌ cup water and stir well so that the jaggery dissolves.
Bring this mixture to a gentle simmer on a low to medium flame. The pineapple pieces should soften. Overall cook for about 5-6 minutes after adding water.
Now add cooked sago or Sabudana, mix everything well. Stir for one minute.
Now add one cup of thick coconut milk. Stir very well and switch off the flame.
Add the fried cashews, raisins and stir well. Reserve a few cashews and raisins for garnish.
Serve pineapple payasam hot or chilled garnished with the reserved cashews and raisins. On cooling, the consistency thickens.