Put the sugar and cardamom seeds in a dry grinder and grind to make a powder. Or use caster sugar and powdered cardamom.
Beat the sugar, cardamom, and ghee using a stand mixer or a hand mixer for 3-4 minutes or until light and frothy.
Add the three flours (all-purpose, chickpea, and semolina) and salt and knead into a soft dough.
Line a baking tray with parchment paper. Break off tablespoon-sized balls from the dough and shape into discs. Place the discs on the baking tray a couple of inches apart. Cover with clingwrap and keep in the fridge for at least an hour.
Preheat the oven to 450 degrees Fahrenheit or 180 degrees Celsius. Remove the clingwrap and place the baking tray in the middle rack. Set the timer to 18 minutes.
When the timer beeps, take out the tray and let it cool down completely. Once cool, put the tray back in the fridge for 30 minutes.
Take out the tray and remove the nankhatai. Store them in an air tight container.
Notes
Do not skip beating the sugar and ghee. This is what makes the cookies soft and airy.
Don't add any liquid (milk or water) to soften the dough. The ghee will do the trick, and you can add a tablespoon more if the dough appears to be dry.
Do chill the prepared discs of dough for one hour before baking. This ensures that the cookies don't spread too much.