Grease the brinjal with oil and roast it over an open flame till it is cooked.
Allow it to cool and peel of the skin of roasted eggplant. Mash the pulp with potato masher or with fork.
For making tadka, heat the ghee in a pan and add chopped onion along with green chilli. Leave few to garnish it.
When onion start to turn pink add chopped tomatoes, coriander powder, red chilli powder and garam masala powder, cook them till tomatoes are pulpy and till the mixture leaves ghee.
Add the mashed brinjal and salt, mix well and cook for 3-4 minutes. Serve hot garnished with coriander and green chili.