In a bowl add in suji, curd, salt and mix it well. Add in water to make batter smooth. Cover and set it aside for 15 minutes.
In a pan heat some oil and add in asafoetida, cumin seeds, mustard seeds, green chillies, curry leaves and mix them well.
Now add in onion, mix it and cook it till onion turns golden brown.
Now add in turmeric powder and mix it well. Next add in peas and potatoes and give it a good mix and let it cook.
Add in dry coriander powder, red chilli powder, garam masala powder, dry mango powder, coriander leaves and mix it well. Once cooked keep it aside to cool down.
Make small patties of the stuffing and keep it aside.
In a bowl take out half off the batter and add in eno fruit salt and mix it well.
Now take a small steel bowl and pour some batter over it, place the stuffing and again pour some batter to cover the stuffing.
For cooking the idli take a pan fill it with water and place a big steel strainer over it.
Place the idli bowls and cover it and let it cook for 12-13 minutes on medium high flame.
Once cooked turn off the heat and let it cool down a bit and then demould it.