Slit large green chilies lengthwise and deseed carefully.
Boil, mash potatoes, and mix with red chili powder, garam masala, and salt.
Stuff potato filling inside slitted green chilies.
Whisk gram flour, ajwain, salt, and water into a smooth, thick batter.
Dip stuffed chilies in batter and deep-fry in hot oil until crisp and golden brown.