Place the sugar and water in a saucepan and let it come to a boil. Lower the heat to simmer, add the cardamom and saffron, and let the syrup cook about five minutes. Check it regularly to see if it has achieved a one-thread consistency. What this means is that when you place a drop of the hot sugar syrup on the tip of your thumb (don’t burn yourself) and touch the tip pf your forefinger to it, the syrup should pull up in a short thread as you separate the thumb and forefinger. If that is too complicated just get yourself a candy thermometer and take the syrup off the heat when the temperature reaches 225 degrees Fahrenheit. Easy.
Heat a nonstick saucepan over low heat. Add the cashew powder and cook, stirring, about two minutes or until it is warmed through. Then add the sugar syrup to it. Turn off the heat and mix well. The mixture will start pulling away from the sides of the pan.
At this point empty the cashew paste on a clean surface, rub some walnut oil on your palms and fingers, and knead the paste a few times until it looks really smooth.
Pat the cashew paste into a greased plate or tray and spread it evenly. The layer should be about a quarter of an inch thick.
Set the plate aside to cool completely, then cut into diamond shapes, the way Kaju Katli is always cut.