Bring milk to a boil, then add lemon juice. The milk will start curdling and the water will separate, keep stirring to avoid burning at the bottom and until the water completely separates. Switch off.
Collect the paneer and transfer it to a muslin cloth, tie and hang it for at least 30mins for all the remaining water to get strained.
Then open and wash it well with water to get rid of the sour taste of lemon. Squeeze excess water.
Then add powdered sugar with this paneer and grind it a smooth paste.
Now transfer this grinded mixture to a nonstick tawa and cook for 10mins (just 8-10mins not more than that). First it will be sticky slowly it will turn into a non-sticky mixture.
Collect this mixture in a bowl , the final stage mixture is called "Makha" - the not yet moulded sandesh. When it is warm make a small ball and flatten it slightly with ur palms. Make a small dent and garnish with pistachios. It will harden while cooling so sure it will not be as fragile as when we mould it.
While it starts turning non-sticky then add saffron strands and mix well. When the saffron is absorbed and is totally non-sticky it will slightly change its texture and color. Switch off at this stage.
This is the easiest paneer sweet I have tried, just few mins and you are done with this yummy milk sweet - Sandesh.