Grind chana dal with ginger, green chily and garlic and make a thick coarsely paste, add little water while grinding (if required).
Mix all the ingredients (potato, onion, coriander leaves, salt, red chily powder, coriander seeds, mango powder and garam masala) together and make a mixture.
Take a big katori and tie a wet muslin cloth around it tightly.
Sprinkle a little water over the muslin cloth and then place one portion of the chana dal mixture on it.
Flatten the chana dal mixture lightly by using wet fingers.
Heat oil in a pan, slide the vada in the hot oil on a medium flame and half fry till light brown colour.
Take them out and let them cool on room temperature or freeze them for half an hour to make a tight shape.
Repeat the same process for remaining vadas.
When it became cool cut the vadas into long strips and deep fry again till they are golden brown and crisp. Drain on absorbent or tissue paper.
Sprinkle Chat masala and serve.
Serve hot with green chutney.
Video
Notes
Note: 1) Kalmi vadas are double fried. 2) Slice vada and double fry before serving. 3) You can refrigerate vada for 2-3 days.