Peel and mash the boiled potatoes.
Heat a heavy bottom pan and add oil, when oil become medium hot then add mustard and urad daal.
When they start to crackle then add chopped cashew,asafoetida, green chilies and curry leaves and stir to mix.
Now add turmeric and the mashed potatoes and mix well.
Now add salt, chili powder, mango powder and the sambhar masala and mix and saute for a minute on medium heat.
Switch off the heat and add chopped coriander and mix.
let the mixture cool down and come to room temperature.
Make small lemon size balls from the potato mix and keep aside.
In a bowl take the dosa batter and add rice flour and all the spices and mix well.
You can add some water if it become too thick, it should be like pakoda batter.
Heat enough oil in a deep pan.
Dip the potato balls in the dosa batter and then drop them in the hot oil.
Let them fry on medium hot oil to a nice golden colour and become crisp and then drain out on a paper napkin to absorb the excess oil.
Serve hot with any tangy spicy dip of your choice or coconut chutney or ketchup.
Enjoy !