Add asafoetida and curry leaves. Add green chillies and ginger.
Stir 30 seconds. Add mashed potato and turmeric. Toss well. Add coriander. Season with salt. Cool. Divide into 8 balls and shape into flattened rounds.
Make batter: combine besan, turmeric, red chilli powder, baking soda and salt.
Add water to make a thick batter.
Heat oil for deep frying on medium-high. Dip each potato ball in the batter.
Fry on medium-high for 3 to 4 minutes until golden and crispy.
To serve: slit pav roll open. Apply dry garlic chutney on one side, green chutney on the other side.
Place one hot vada inside. Optionally add a fried green chilli alongside.