Take sooji and yogurt in a bowl and mix well. Set aside for 5 mins. Now add in water to reach the perfect thick consistency. Add salt and mix well. Set aside for 30 minutes.
Make tempering, heat some oil and crackling in the spices. mix well. Pour it into the batter and mix well. Add little baking soda and mix well.
Now grease idli plate lightly with oil and place cashews in the centre. Spoon batter in and steam cook for 5 to 8 mins.
Now remove the plates and remove the idlies carefully using a spoon. Serve hot with chutney.