Remove the skin of the pumpkin, deseed and grate it until you have the required quantity. In a thick bottomed pan, heat 2 tablespoons of the ghee and fry the cashew nuts until they are golden brown. Set aside.
Fry the grated pumpkin without adding water (the moisture content in the pumpkin is more than enough to cook the entire recipe). Make sure the pumpkin gives off its moisture. This will take about 10 minutes. Meanwhile, boil the milk then add to the pumpkin, stirring all the time. After 2 minutes, add the remaining ghee and keep stirring.
After a further 2 minutes (when all the contents have been well mixed) add the sugar and keep stirring until it dissolves. Add a few strands of saffron, the cardamom powder, edible camphor and fried cashews and cook until the ghee oozes out and floats on top. Leave the mixture over a low heat for about 5 to 8 minutes then transfer the halwa to a serving bowl and garnish with pistachios.