Combine the rice flour and sugar and add to a saucepan containing the milk. Slowly bring to a boil whisking vigorously for about 2 minutes, taking care not to scorch the mixture.
Add cardamom and saffron and continue stirring for 1 more minute.
Remove from heat, and add rosewater.
Pour pudding into individual serving glasses and let cool completely. Refrigerate for about 2 hours. Top surface completely with finely chopped pistachios and serve.