Sieve the besan flour in a mixing bowl, add baking soda and ghee. Add water gradually and mix to form a smooth, flowing batter. The batter should coat the back of a spoon easily. Rest for 7-8 minutes.
Remove few spoons of batter in 2 small bowls. In the big bowl of batter add yellow/orange color and mix well. In the small bowls, add green and red food colors respectively and mix well. This will create three colored batters.
Heat ghee/oil in a kadhai/pan for deep frying. Hold slotted spoon over hot oil, do not let to touch the oil.
Drop spoonsful of the batter over slotted spoon into the hot oil, it will create small pearls/boondi. Fry until golden brown all over on medium flame. Drain on paper towel and keep aside.
In another pan, make a one-thread syrup by combining sugar, water and saffron. Cook until it reaches to the boil. Add cardamom powder and cook until 1 thread consistency. Do not cook the syrup too much.
Add the fried boondi to the sugar syrup and mix well. Cook for 2-3 minutes until the boondi absorbs the syrup. Cover the lid for 2mins.
Finally add chopped nuts of your choice and mix well.
Grease your hands with ghee and shape into round laddus while the boondi is still warm.
Allow to cool completely before serving the boondi laddus. Store in an air-tight container for up to a week. Enjoy!