Soak yellow and black mustard seeds for 20 minutes. Make a paste of the mustard seeds, salt and green chilies and let it sit for about 30 minutes.
In a kadai, add two tablespoons of mustard oil and heat it.
Fry the eggplant slices and keep them aside.
To the remaining hot oil, add the nigella seeds and let them splutter
Now, add the potato slices to the kadai and saute them till they turn golden brown at the edges.
Add the drumsticks and continue sauteing them for about a minute.
Now, add about half cup of water to the kadai till the vegetables are almost completely done.
Now, add the mustard paste to the kadai followed by the sauteed eggplants.
Continue cooking on medium flame till the chochori becomes semi dry. Adjust the seasoning.
Turn off the flame and serve.