Heat a pan with 2 tsp ghee. Once it melts add cashew nuts and roast till golden brown. Transfer to a bowl and set aside.
To the same pan add remaining ghee, rava and roast till it changes to light brown colour.
Add 1-½ cups water (at room temperature) and mix well ensuring there are no lumps. Close the pan with lid and let it cook well over medium flame for 2 to 3 mins. Rava should get cooked well and it should be soft to the touch. It will be in thick porridge like consistency.
Add sugar and mix well. The rava mixture will start to loosen up further as the sugar melts. Once the sugar melts completely, simmer the flame completely.
Add milk, crushed cardamom, edible camphor, ghee roasted cashew nuts and mix well. Cook for 1 to 2 mins and switch off the stove.
Garnish rava payasam or sooji kheer with saffron strands and serve hot, warm or chilled.