Grind all the ingredients with enough water except the vegetables and oil.
Make a smooth batter of a medium consistency, do not make it runny as you cannot make them crisp. Too thick batter with result in very thick chana dosa and will be unable to spread the batter when you make them.
Heat a pan with 1 tsp oil, add the vegetables and salt. Fry them on a high flame for 2 to 3 mins, till they are partially cooked to retain the crunchiness of veggies. Off the flame and set aside.
Grease a non-stick flat pan / dosa tawa and heat it till smoky hot.
Drizzle few drops of water, set the flame to medium, pour a ladle full or 1/3 cup of batter and spread the batter evenly with the base of the ladle to get a 7 “ dosa.