In a wide heavy bottom pan or iron kadai, dry roast the walnuts on low heat for 6-7 minutes. Transfer to a plate and let cool down.
Once cooled, using a sharp knife, finely chop the walnuts (don't powder).
Add 5 tablespoon of ghee to begin with to the kadai and add the besan. Continuously stirring, roast the besan in ghee for about 10-12 minutes or until its golden and you smell a nice aroma.
Add the chopped walnuts and mix thoroughly with the besan. Roast everything togther for another 2 mins and then switch off the stove.
When the mixture is cool to touch(but not cold), add the sugar and cardamom, and mix everything with hands thoroughly.If you feel that the mix is dry, add more ghee and mix well (I used about 7 tablespoon ghee in all). If you feel that the mixture is getting hard to handle, refrigerate it for 30 minutes and use again.
Divide the mixture into portions and using your palms and fingers, form into ladoos of desired size without cracks.(but do not squeeze hard)
Store in an airtight container for upto a week. If its summer, store in fridge. You can freeze for a month too. Enjoy.