Powder the cashew nuts in a mixer grinder, in small batches.
To make this mithai use whole cashews or broken pieces of Kaju.
Take care that you do not pulse it for a long time or the cashew nuts would release its oil and it would turn pasty.
Sieve the cashew nut powder and keep aside (do not use a fine sieve for this).
In a non-stick pan heat sugar and water till the sugar dissolves.
Add the cashew nut powder and mix well (there is no need of any string consistency of sugar syrup).
Add cardamom powder and stir. Break lumps, if any, while stirring. Keep stirring the mix till it comes together and starts forming a soft dough like consistency.
This would take around 8-9 minutes of stirring over medium to low heat.
Transfer this lumpy dough to a work surface or on a greased plate.
When the dough is still warm (or a bit hot, as long as you can handle it) add 1 tbsp of melted ghee, start kneading it lightly.
You may grease your palm with some ghee before kneading. Kneading will smoothen out the dough, do not overdo it.
If you find the dough to be hard add a tablespoon of milk and knead to soften it.
Flatten this dough with your palm and start rolling it by keeping it in between two parchment papers (butter paper) before rolling it.
This would give a smooth texture to the Katli.
Ensure that the dough is warm while rolling or it would be difficult to roll the cooled dough.
Gently roll the dough to a thickness of 3 to 5 mm.
As the katli cools, carefully measure and mark the katli using a scale. Cut it using a sharp knife, in diamond or square shapes.
After it cools completely, gently remove the Kaju Katli slices.
Serve or transfer the slices to airtight containers and store for further use.