Making Sweet Chutney
Soak tamarind in hot water for 30 to 40 minutes.
With your hands, squeeze the pulp from the tamarind in the same bowl or pan. strain the pulp and keep aside.

Heat oil in a small pan. lower the flame & add cumin seeds and let them crackle.
Add ginger powder, red chili powder, asafoetida. Stir and add the strained tamarind pulp. Cook for 2-3 minutes.
Add the jaggery and salt and cook for 4-5 mins more. The mixture would thicken. Let the saunth chutney mixture cool.
When cooled, store the saunth chutney in an air-tight dry jar or container. Refrigerate and serve the saunth chutney whenever required with chaat or snacks.

Making Potato Stuffing
Boil or steam potatoes in an Instant pot, pressure cooker or pan until they are completely cooked. Peel and then mash them with a fork in a bowl.
Crush garlic and green chillies to a semi-fine paste in a mortar-pestle.
Heat oil in a small pan. Add mustard seeds and crackle them. Then add curry leaves and asafoetida. Stir and fry for about 5 seconds.
Then add crushed garlic and green chilies paste, which have been crushed in a mortar-pestle. Add turmeric powder.

Stir for some seconds until the raw aroma of garlic goes away. Do not brown garlic.
Pour this tempering in the mashed potatoes.
Add chopped coriander leaves and salt.
Mix everything well and then make small to medium balls from the mashed potato mixture. Flatten these balls a bit. Cover and set aside.

Making Batter
In another bowl, make a smooth and thick yet flowing batter from the besan, turmeric powder, asafoetida, a pinch of baking soda (optional), salt and water.
The batter should not be very thick or thin. If the batter becomes thin, add 1 or 2 tablespoon of gram flour. If the batter becomes thin, then add 1 or 2 tablespoon water. Set aside.

Frying
In a kadai or pan, heat oil for deep frying.
When the oil becomes medium hot, then dip the slightly flattened potato balls in the batter and coat it evenly with the batter.
Gently and carefully add these batter coated potato balls in medium hot oil.
Depending on the size of the kadai or pan, you can add more or less of the vadas while frying. Don't overcrowd the pan while frying.

When one side becomes crisp, lightly golden and firms up then gently turn it over with a slotted spoon and fry the second side. Turn over when the second side is fried.
This way turning a couple of times fry the batata vada till they are evenly golden on all sides.
Drain them on kitchen paper towels. Make all batata vadas this way and keep aside.
When they are still hot or warm, you need to serve them. Take all the chutneys and pav on your work surface.

Assembling & Serving
Slice the pav without breaking it into two parts and keep aside. If you don’t have sweet chutney, then just make the vada pav with green chutney.
Spread both the green chutney and sweet chutney on the sliced pav. You can also spread green chutney on one side and sweet chutney on the other side.
Sprinkle the dry garlic chutney. This is optional and if you don’t have you can skip it.
Place the hot batata vada sandwiched in the bread slices.

Serve vada pav immediately or else pav becomes soggy. You can also serve some fried salted green chillies and both the chutney along with it.