Wash and soak the rice for at least 1 hour, ideally overnight. Drain and keep to the side.
In a large pot, add water, rice and salt, bring to a boil on high heat, and then then leave to simmer on low heat for about 45 to 60 minutes. Occasionally stir to stop the rice from sticking to the bottom of the pot.
Once most of the liquid has evaporated, stir in the sugar, rose water, ground saffron, cardamon powder, butter and slivered almonds. Continue simmering for an additional 30 minutes on medium-low heat until the sugar has fully dissolved and any excess liquid has evaporated. Make sure to stir occasionally to avoid the rice from sticking on the pot of the pot.
Spoon the rice pudding into individual cups and leave to cool. Garnish with ground cinnamon, pistachios and almonds.