Boil the milk in a big pan and stir continuously. Once the milk starts boiling, lower the flame.
Pour the lemon juice or vinegar. Stir the milk.
Once the milk starts curdling, and it changes into chenna (cottage cheese) and greenish water, remove the pan from flame.
Leave the chenna / channa in this condition for 5-7 minutes.
Put it over a soft cotton cloth / or a cheese cloth (if you have any). Let all the water drain away.
Now put this cloth with the chenna under running cold water for 2-3 minutes. This will help to remove the smell of lemon.
Hang the chenna along with the cloth on the kitchen tap / faucet for 30 minutes.
Please note that the Chenna shouldn’t get too dry. If it gets dry, the Sandesh won’t be soft enough.
Now in a big bowl, take the chenna out, add sugar and mix it nicely.
Once it gets soft and smooth, add the cardamom powder. Again knead it nicely, until you feel oily on your palm.
Add the chopped pistachios. ( you can use food processor for the mixing and kneading )
Take a steel container, grease it with non-stick spray or butter. Pour the cheese mixture into the container, sprinkle the saffron strands and cover it with lid.
If you don't have any container with lid, take a cake mould and cover it tightly with aluminium foil.
Take a Idli cooker add 2 cups water and place the container carefully.
Cover the cooker's with lid. Let it cook on low to medium heat for about 15 to 20 minutes.
Once it is done, let it cool down first at room temperature. Then put the container into the refrigerator for half an hour.
Cut it into the pieces. Bhapa Sandesh is ready!! Sprinkle or decorated with some dry fruits and serve!