Place the rice in a sieve and rinse well under cold running water. Put it into a large, heavy-based saucepan, add the milk and bring the mixture to the boil. Reduce the heat to low and simmer, uncovered, for 10 minutes.
Add the sugar or honey to the rice, stir until it has dissolved and continue simmering, uncovered, for 55 minutes, or until the rice is almost soft and most of the liquid has been absorbed. From time to time, stir in the skin that forms on the top.
Stir in the coconut cream, lime zest and juice and the orange flower water, if using. Remove the pan from the heat and allow the mixture to cool for 20 minutes. Serve warm, or chill it for 1 hour and serve cold, with mango slices, if liked.
Tip: glutinous black rice, which produces dishes with a wonderful dark purple, almost black, colour, is sold in Oriental food shops.