Take 5 cups of full fat whole milk in a thick bottomed pan and heat the milk on low to medium flame, till the milk starts to froth or form a layer of malai on top.
With a spatula, gently move the cream layer from the top, when it starts to float on the top. Bring it towards the sides of the pan and stick to the pan.
keep on simmering the milk like this and collecting the cream layer on the sides.
Meanwhile soak almonds and pistachios in hot water for 30 minutes. After 30 minutes remove their peels. Chop them and keep aside. Do keep check on simmering milk as well. otherwise it will stick to the bottom.
this process of collecting the cream layer has to be done many times. In between also stir the milk gently on occasions, so that the milk does not get burnt from the bottom. if you do too much of stirring and if quickly, then you won't get the layers of cream in the rabri.
once the milk reduces to half, then add sugar. you can add sugar as per your taste.
Add saffron strands and cardamom powder. stir gently.
Continue collecting the malai and bringing it to the sides of the pan. also do stir the milk gently after you bring the cream towards the sides of the pan. if you don't stir the milk then there is a possibility of the milk getting browned or burnt from the bottom.
when the milk gets reduced to 1/3 or 1/4 of its original quantity, then switch off the flame.
The malai layer will be collected on the sides. Scrape off the entire malai layer as well as dried milk solids and add to in the thickened milk.
Add almonds and pistachios and rose water in it and stir gently. let it cool down.
Layer it with crushed ice in a glass or in a bowl. Garnish with some chopped dry fruits. Serve chilled. Enjoy. ☺