In a plate put all the stuffing ingredients - grated onion, desiccated coconut, roasted peanut powder, sugar, kalonji (nigella seeds), ginger garlic paste, coriander powder, red chili powder, turmeric powder.
Mix them all. Add chopped coriander.
Mix them well with light hands.
Peel potatoes and slit them vertically and horizontally till 3/4th depth. Take brinjal and remove the stem and slit them vertically and horizontally till 3/4th depth. Now fill the prepared stuffing in them carefully. If the brinjals are big then cut them into half and then slit them as above and fill the stuffing. Keep aside the left over stuffing.
In a thick bottom pan or non-stick pan heat oil, add mustard seeds and cumin seeds.When they crackle add turmeric powder and asafoetida.
Put the stuffed potatoes into it and toss them well and cook them covered for 5-7 minutes or till semi soft.
Now once the potatoes are semi soft add the stuffed brinjals. Toss them well. (potatoes take more time to cook then brinjal and hence we semi cook them first and then add brinjals to them).
Cover and cook potatoes and brinjals till done.
Now add the left stuffing mixture to them. Toss them gently and cook for 3 -4 minutes.
Add the chopped coriander and remove from heat.
Serve the hot bharwan baigan aloo with roti of your choice. I have served it with jowar roti.