Heat a heavy bottom pan/wok on low to medium heat. Add the besan flour and cook for 8-10 minutes, stirring constantly. Roast the flour until we can smell a nutty flavor. It will get a little lumpy which is fine and as it roasts the color will begin to change.
Once it is evenly roasted, add the ghee and stir again, making sure to distribute the ghee evenly in the flour. Be patient here and stir it well. All the flour should to be coated in the ghee.
Let this mixture cook for 5-6 minutes, stirring constantly. It will be dry at first and slowly start getting smooth and become like a paste.
Take it off the heat and transfer to a thali or large plate, add the jaggery and cashew nuts, stir the mixture well. It will take a couple of minutes however you want to work quickly as the heat from the flour and ghee mixture will dissolve the jaggery better.
Once the mixture is not as hot, switch to using your hands to mix everything. Using a tablespoon, portion the mixture in your palm and squeeze it together repeatedly to form balls. Top with a cashew nut and set aside. Repeat until the mixture is done.
Store in an air tight container for 1 week at room temperature or 2 weeks in the fridge.