In a pan, add sugar, water, rose water and green cardamoms and make a semi thick syrup on medium flame.
In another pan, add clarified butter (ghee) and heat it up.
Add semolina (suji) in ghee and roast it for few minutes on low flame
As the suji starts changing color and gets aromatic.
Add hot sugar syrup and stir continuously. (Sugar syrup will add sweetness and work as a binding agent to make sooji blocks).
Grease the mould with oil. Place the halwa in the mould.
Immediately set it using a spoon or spatula otherwise it will be hard and become difficult to set.
Garnish with desiccated coconuts and pistachios.
Again set with the spoon. Rest it for 5 minutes.
Cut into desired slices. Again rest it a few minutes to get hard. Take the slices out and serve.