Heat mustard oil in a pan or handi.
Make a roughly grounded paste of ginger-garlic-coriander-green chilli in a mortar pestle.
Add the paste to the oil and cook for a min on a low flame.
Next add the onion puree and allow to cook till golden brown. Keep stirring in between to prevent it from burning.
To flavour the gravy, add in the spices – turmeric powder, red chilli powder, coriander powder, amchur powder, garam masala powder and salt.
Mix everything well and cook on a low flame for half a min., make sure not to burn the spices.
Next add tomato puree. Mix well.
Cover and cook for 5-6 mins. Keep checking and stirring in between so that the masala doesn’t burn.
Uncover and cook till the masala starts to leave the oil from sides.
Add diced potatoes (strain the water if you have soaked in it). Mix well and cook for 4-5 mins.
Finally add baingan (strain water before adding). Mix well.
Add water as required.
Cover and cook till everything is well cooked.
Keep checking and stirring in between to ensure the sabzi doesn’t stick to the bottom of the pan and cooks evenly.
Finish with lots of coriander for the added freshness.
Serve hot with rotis or parathas.