Pour the milk in a saucepan and bring to a boil, stirring constantly and scraping the sides to prevent scorching.
Reduce the heat to low and simmer for approximately 40 minutes or until the milk has reduced to half its original volume.
Stir in the sugar, saffron, cardamom.
Crumble up the bread as fine as possible- using a food processor is ideal. Add the bread and continue to boil the mixture until the bread has integrated into the milk and appears to have dissolved. The mixture should thicken and resemble the consistency of melted ice cream (If you feel as if it hasn’t thickened much after adding in the bread, in a small bowl, add 2 tbsp of the boiled milk to the cornstarch and stir until dissolved. Add the cornstarch mixture to the milk mixture and boil until thicker).
Use an immersion blender to process the mixture and remove lumps of bread or spices. Alternatively use a food processor.
Stir in the pistachios and pour into desired containers such as Popsicle molds (I like to fill plastic cups around halfway with the mixture in place of Kulfi molds).
Cover the surfaces with saran wrap and place in the freezer for a minimum of 6 hours or overnight. Remove kulfi from molds and serve.