Wash and soak sabudana for 5 - 6 hrs. Drain out water and air dry on a clean plate. Dry for 30 minutes to 1 hr.
Boil potatoes for 5 whistles or till completely boiled. For better results boil them well in advance and cool before adding to other ingredients. It will help in binding properly.
Once cold, mash the potatoes completely and keep aside.
In a mixing bowl mix all ingredients and mix them well. Divide into equal size balls.
Give them shape of patties by pressing lightly with palms. Press the edges also.
Heat oil in a deep frying pan. Put the vada into hot oil one by one without overcrowding.
And deep fry till both ends are crisp and light brown in color.