When the brinjals are nearly half way through, heat the oil for the gravy in a pan and add the whole cumin seeds, bay leaf and the whole red chilli.
When the seeds begin to splutter, add the onions and peanuts and fry till the peanuts leave their aroma and dark spots start to appear.
Add the tomatoes, garlic, roast cumin, chilli powder(if using any) and turmeric and season with salt. Stir and cook covered over low heat till the tomatoes are mushy. Stir in between.
Add the water and bring to a boil. Transfer to a food processor and pulse, along with the whole spices. Do not make it too smooth, just make sure that the spices have ground properly.
Transfer the gravy to the pan over heat and bring to a simmer over medium heat.
Add the brinjals, coat them with the spices and cook for a couple more minutes, stirring often (the gravy will tend to stick to the pan). Add more water if necessary and cook till the brinjals are completely done.
Add the garam masala powder, stir and remove from heat.
Garnish with coriander leaves before serving.