For red chutney, grind together coconut, red chilli powder and garlic in a mixer. Heat oil in a non stick pan, add this mixture and sauté for a minute. Add the gram flour crumbs and mix well and remove from the heat. Season with salt. Set aside to cool.
Grind together green chillies and garlic to a paste. Mix the potatoes, garlic-green chilli paste, turmeric powder, asafoetida, lemon juice, coriander leaves and salt in a bowl. Divide into eight equal portions and roll them into balls.
Mix together gram flour, soda bicarbonate, turmeric powder, red chilli powder and salt in a bowl. Heat one-tablespoon oil and add it to the gram flour mixture. Add sufficient water and whisk to make a coating consistency batter. Heat sufficient oil in a kadai.
Dip the potato mixture balls in the batter and deep fry in hot oil till golden brown in colour. Drain on an absorbent paper. Slit the pavs horizontally without cutting through, spread the red chutney on the inner sides of the pav and stuff it with hot vadas. Serve hot.
or the red chutney reserve the gram flour crumbs (besan boondis) obtained during the frying of vadas. Remove excess oil and allow it to cool.