Grease a baking pan or glass container with butter or ghee and line with parchment paper.
Keep the parchment paper edges bigger than the pan, so it is easy to pull Kalakand out of the container. Set aside.
Before starting to make Kalakand, crumble the chhena.
In a non-stick pan or thick base pan, take crumbled chhena. If you use a store-bought paneer, grate it and use it instead of chhena.
Add condensed milk, ground pistachios, milk, and saffron strands. Mix well and cook on low to medium heat, stirring continuously.
Once the mixture starts thickening, taste it, and add more condensed milk at this stage if you prefer it sweeter.
Continue cooking and stirring until the mixture becomes thick like a big lump and stops sticking to the pan. Depending on your stovetop's heat, it will take approximately 10-15 minutes or a little more or less time.
Do not overcook; the mixture should be moist and a little sticky. Once it becomes a thick mass and stops sticking on the sides of the pan, turn off the heat.
Now add rose water and cardamom powder, mix well.
Pour this mixture into greased pan or container. Spread it evenly and smooth the top. Then sprinkle chopped pistachios.
Refrigerate Kalakand for a few hours or at least for 2 hours. Once it is set, pull it out from the pan. Cut the Kalakand into the desired shape and size.