Let the mixture turn completely cool and set for about 30 minutes.
Cut into squares in the desired size.
Notes
Citric acid, Nimbu Sat or Tatri, whatever you call, is one and the same thing available in the market in different looks. Tatri and Nimbu Sat are the names for Citric Acid in hindi. Citric Acid is available in the market in the form of a powder whereas Tatri, also named as Nimbu Sat, is available in crystals. We preferred Tatri over Citric Acid because Tatri is more economical and pure being in a raw form and also easily available.
Jammu chocolate has a dark orange (like a sky look while sunrise/sunset) which you can get by mixing red and yellow food colours. While adding food colours in mixture, don't add both the colours in one go. Few drops of both colours first, check the desired results, and proceed accordingly. You may need to add both colours in different quantity than ours depending upon the basic colour of Khoya you are using. Our Khoya is bright white so had to use much colours but you keep a check on your's.
Why only Magaz and pistachios (that too, too less) for garnishing... because this is the tradition look of Jammu chocolate. We have rarely observed cashews, almonds or any other dry fruits sticking over it. Not even silver verk is used. Only good quantity of magaz and very very less pistachios.
If at any stage you will find that the mixture is becoming dry, add water just by spoon/s to maintain the consistency.