Take 250 grams of cashews and grind them into a fine powder using a mixer-grinder. Make sure not to over-grind, as it may release oil from the cashews.
In a non-stick pan, add 250 grams of sugar and 1/2 cup of water. Cook on medium heat until the sugar dissolves completely and forms a syrup of one-string consistency.
Add the cashew powder to the sugar syrup and mix well, ensuring there are no lumps. Cook on low heat for 5-7 minutes, stirring continuously.
Add 2 tablespoons of ghee to the cashew mixture and cook for another 2-3 minutes until the mixture thickens and starts leaving the sides of the pan.
Grease a flat plate or tray with ghee and spread the cashew mixture evenly on it. Allow it to cool for a few minutes.
Place a butter paper or parchment paper on top of the cashew mixture and roll it gently with a rolling pin to achieve a uniform thickness of about 1/4 inch.
Remove the butter paper and let the mixture cool completely. Once cooled, cut the kaju barfi into diamond-shaped pieces using a sharp knife.