To make Kulfi, first in a blender grind pistachio to a coarse powder. Transfer to a bowl and set aside.
Now in a heavy-bottomed saucepan heat milk over low heat. Add cardamom powder, saffron, and keep on stirring the milk occasionally. Let it simmer over low heat till it reduces to half the original quantity and thick in texture.
Once milk thickens, add grated khoya, sugar, and pistachio powder. Stir to mix nicely. Simmer the milk till sugar and khoya are nicely dissolved in the milk. Taste and add more sugar if required. Turn off the heat
Let the kulfi mixture cool down to room temperature.
Pour the liquid into the Kulfi molds or in an airtight stainless steel or glass box with a tight fitting lid. Set Kulfi in the freezer for 5 – 6 hours or best overnight.
Kulfi molds come with lids. So if you want to insert an ice cream stick in the kulfi, do not put the lid. Cover the top of the mold with aluminum foil and insert a skewer or ice cream stick poking a hole in the aluminum foil.
To serve or to unmould the Kulfi, allow the kulfi molds to remain at room temperature for a few seconds or rub them between your palms for a few seconds. Then unmold the kulfi or pull out using the ice cream stick inserted.
Serve kesar pista kulfi chilled.