Crush each mangodis into 2 to 3 chunks.Then cut the brinjals in small chunks as well.Drench them in water to prevent from turning black.Peel the potatoes, wash and chop them in small chunks.Heat 2 tbsp oil in a pan and stir fry the mangodis on medium flame.Keep stirring constantly and roast the mangodis until you see a little change in color.When the mangodis are roasted well add ½ cup water, followed by potatoes, brinjals and salt.Stir to mix everything well.Cover and let it simmer for 5 minutes. Stir at regular intervals.Meanwhile in another pan, let us prepare a masala. For this, heat 1 to 2 tbsp oil in a wok or pan and splutter cumin seeds first.After the seeds crackle add asafoetida, ginger paste, turmeric powder, coriander powder, tomato-green chilly paste, red chilly powder and some salt.Now saute for a while until you see oil leaving the edges of masala.After sautéing the masala, add 1 cup water and let it simmer.When you see gentle boil in the gravy, add garam masala and cooked veggies into it. Mix well.Add some coriander as well. Cover the sabzi and let it cook for 4 to 5 minutes.Potato-brinjal mangodi sabzi is ready, transfer it to a serving bowlGarnish with some green coriander and serve piping hot and tantalizing potato-brinjal mangodi sabzi with chapatti, parantha, naan or rice and relish eating.