Cook the sugar and water together in a flat pan and bring it to a boil.make a 2 and 1/2string consistency of sugar syrup by stirring on a low heat for 5-7mins.then remove it from the heat.
Next add in the grated khoya to the hot syrup.stir it continuesly with a wooden spoon for 3-4mins and the mixture will start to thicken and turn to a soft paste.while it's still runny.return it to the heat. Add in the Pista colour.cardamom and stir on a very low heat for 2mins.
Transfer this mixture to a greased tray or plate.keep 1/2of this thick Burfi aside to set for 10-15mins in the freezer.
Next cut the Chocolate and put the chocolate in a double boiler.start melting the chocolate but do not over melt it.
Once the plain Burfi is set pour the melting chocolate layer on top and spread the crushed chocolate and Pista on top. Keep it aside for 10mins in the freezer.
Cut the varak on Burfi into equal pieces and place it on top of the Burfi then transfer to a plate and let it cool.