cut the onion, green chilies, coriander leaves, ginger and keep aside.
take a mixing bowl, add 1 cup of semolina/sooji/upma rava.
add salt as needed, 1/4 tsp of cumin seeds and a pinch of baking soda.
put the chopped onions, green chilies, coriander leaves, ginger and mix well.
add 1/2 cup of yogurt and mix.
then add yogurt little by little until you get the correct consistency.
the batter should not be runny or too hard.
leave the batter for 15-20 minutes and later mix the batter again.
heat oil for deep-frying.
when the oil is hot, take a lemon-sized batter, make into flat round shape.
leave them into oil carefully.
deep-fry (on medium heat) the vadas until they turn into nice golden brown color. Flip them in between.