Boil the milk till it bubbles. Meanwhile, mix the lemon juice in 1/4th cup of warm water. Add the mixture of water+lemon juice into the boiling milk.
As soon as the fat separates, turn off the heat and pour the Paneer formed into a muslin cloth. Wash it wil cold water and keep it under a heavy pan for 1hr
Now mash the Paneer and knead it to form a dough, add the sugar and cocoa powder and knead again. Now cook the paneer mixture on a low flame for 6-7 minutes till it is non sticky. Cool the mixture and form the roundels.
Now heat white chocolate, butter and cream on a double boiler, to form a syrupy consistency, and pipe it over the sandesh.