In a large thick bottomed pan heat 2 litres of whole milk.
When the milk comes to a boil, lower the heat and add juice of 1 lime and constantly stir. Stir gently while adding the lemon. (If the milk doesn't separate, add another tablespoon of lemon and boost up the heat a little, the milk will separate.)
Now you will see the chana and the whey separate. Remove the pot from the heat and carefully pour it over the muslin cloth. Now run it under cold water for 1 to 2 minutes to remove the lemony flavour. Squeeze out as much water as possible.
Now tie the loose ends of the muslin cloth and hang it to the tap to drain the excess water for 30 minutes. Make sure that the chana doesn't turn too dry.
Place the chana in a large flat plate and with the palm of your hands start kneading the chana/cottage cheese for 10-20 minutes until it turns smooth and soft.
Now add the nolen gur/date jaggery to the cottage cheese and start mixing with your fingers and palm of your hands until everything is mixed and combined together.
Add the chana and gur mixture to a non stick pan and cook on low heat stirring continuously for 8 to 10 minutes.
The mixture will be of uniform consistency and pull away from the sides of the pan.
Take it off the heat and let it cool a little to handle.
Brush the sides of the mould with some ghee. Take a small ball of the Sandesh and shape with the moulds.
Garnish with some pistachios if desired(optional). Ser it immediately or at room temperature.