Heat the ghee in a heavy bottomed pan and add the cashew nuts to it. Once the cashews start to turn slightly brown, add the raisins and as soon as they puff up, take them out of the ghee using a slotted spoon and save in a small bowl.
In the remaining ghee, roast the vermicelli for a couple of minutes. Add the milk and let it come to a boil.
Lower the heat to medium-low and keep cooking till the milk thickens a little, for about 15 mins.
Add sugar and cook till all the sugar is dissolved.
Remove the cardamom seeds from the pods and crush them well. Add them to the payasam and add the roasted cashew nuts and raisins.
Serve warm or cold
If you did not buy the roasted vermicelli but bought the regular vermicelli instead, no worries. Just roast the vermicelli in a little ghee till its slightly brown. Be careful to not let it burn.