Grind kaju (cashews) to a fine paste (powder). Do not add any water while grinding. Keep aside.
Take sugar in a pan and add water. Boil till a single thread syrup is formed, about 3-4 minutes after teh syrup starts boiling.
Mix kaju paste into the syrup, break balls (lump) with a spoon moving it in circular motion, stir well. Switch off the burner and let it cool so that it becomes thicker.
Transfer it on a greased surface and roll it with a rolling pin to about 1/8" thickness.
Let it cool and apply silver foil gently.
After about 1-2 hour, cut the katlis into diamond shape.