In a big mixing bowl , take all the dry flours ie jowar flour , rice flour , rava , grated ginger , chopped chilli , curry leaves , coriander leaves , cumin and salt . Don't add onion .
Add some water and / or butter milk . Mix well so that no lumps are formed .let it sit for 5-10 mins . Mix and check the consistency. The batter should be thin like that of rava dosa batter.
Heat a tawa or nonstick pan. When the tawa is hot , rub it with a drop of oil using an onion piece. Sprinkle onion pieces .
To the hot tawa pour a ladle full of jowar dosa batter in circular motion.Start pouring the batter from the outside rim of tawa to inwards center of tawa. As the batter is thin ,it will become lacy .( The method of pouring this dosa is similar to rava dosa) .Smear a few drops of oil around the dosa.
Lid the pan and cook it on a medium flame.Cook till bottom side starts to turn golden brown.Once it becomes crisp ,just fold and serve . No need to flip .
Remove from tawa and serve hot Jowar dosa with chutney / chutney powder or sambar .
You can add any other veggie too to this like grated carrots / finely chopped capsicum etc.
If you are a beginner you could find it little difficult to make thin crisp dosas. Also it could happen that you are finding it little difficult to remove dosa from the tawa. Those people can start with making the batter not too thin. That way dosas wont come thin and crisp . It will be soft and easy to handle. Don't worry once you start getting a hold on it you can stat making the batter more thin and relish crispy crunchy dosas.
If using iron tawa , pour the dough when it is very hot . You will get nice lace texture. If using non stick tawa, pour when medium hot . And for both cook in medium low flame . that way they will become crisp.
Rubbing onion to the hot tawa imparts nice flavor to the dosa as well prevents dosa from sticking to the tawa. This tip holds good while making any dosa.