Step 1Bring the milk to a near a boil in a heavy-bottomed pan. Decrease the heat to medium-low and let the milk bubble--but not bubble over. Whenever a creamy crust forms at the top, simply mix it into the milk. Stir the milk occasionally until it thickens to about one-fourth of its original quantity and turns light brown in color, about 2 hours. (It will look a little curdled.) Turn off the heat.
Step 2Add the sugar and cardamom. Stir until the sugar is completely dissolved.
Step 3Lightly heat the ghee in a skillet over medium heat and fry the cashews and pistachios until they turn golden brown, about 2 minutes. Place the nuts on a paper napkin until the ghee is absorbed. Add the nuts to the reduced milk and allow the mixture to cool completely, about 1 hour, stirring occasionally. Transfer into a serving bowl and garnish with saffron. Cover and refrigerate at least 2 hours. Serve chilled.