Start by slicing the brinjals and soaking in salted water for 10-15 minutes.
Pound the ginger garlic and chili together.
Heat some oil in a pan, add the mustard seeds and curry leaves. Once it pops, add the ginger garlic chili paste and saute to 30 secs.
Now add the brinjal slices, a little salt and cook for 6-7 minutes till soft and done.
Once brinjals are done, add 1/4 cup water to it and cover the lid immediately. Let it come to room temperature. In the meanwhile, make the yogurt.
To yogurt, add 1/4 cup water and all the listed ingredients. Mix thoroughly. Taste and adjust according to taste.
Once the brinjal is cooled, add the whole thing to the chilled yogurt mix. Stir through well and keep cold till serving time.