Clean and boil potatoes in a pressure cooker along with water at medium to high heat for 3-4 whistles. Once boiled, turn off the heat. Cool down the pressure cooker under cold tap water and take out the potatoes immediately. Let potatoes cool down. Peel and mash the potatoes using a potato masher. Keep aside.
Grind chilies, ginger-garlic, coriander leaves, mint leaves along with very little water till it has a puree consistency. Keep it aside.
Heat oil in a pan or kadhai at medium heat. Once the oil is hot, add mustard seeds. Once the mustard seeds start crackling, add curry leaves. Saute for few sec. Add coriander, garlic and mint puree into it. Saute it for 1 minute.
Add turmeric powder, chaat masala powder, salt and saute till masala gets thick and all the moisture evaporates from masala.
Add crushed coriander seeds and mix it well. Turn off the heat.
Add boiled and mashed potato into the masala and mix it very well.
Lastly, add lemon juice and coriander leaves and mix very well. Let it cool down.
Make 20, equal size, small potato balls or your desired size. Keep them aside.
To make batter: In a mixing bowl, add gram flour, rice flour, garlic paste, chili powder, salt, turmeric powder, coriander-cumin powder and some coriander leaves. Mix it well using a wire whisker.
Add water little by little and make a lump free batter. Batter should be not very runny and not very thick. It should have medium consistency. Add baking soda and mix gently very well.
Heat oil in a frying pan at high heat. Once the oil is hot, reduce the temperature at medium heat. Drop one potato ball into the batter, coat it very well with batter then drop it into hot oil.
Drop 5-6 balls at a time following the above process.
Fry the potato balls from all sides until it gets a golden color.
Once its done, take out all the potato balls from the hot oil.
Place them on a paper towel to absorb excess oil. Make rest of the batata vada following the same process.
Batata vadas (Aloo bondas) are ready to be served.
Enjoy it with vada pav along with garlic, mint and tamarind chutney.