Roast eggplant until eggplant is blackened (on bbq, under broiler, on open flame burner)
Remove eggplant and remove skin once it has cooled
Place the eggplant in a food processor, add the homemade curry powder, whiz to almost puree, and set aside
Set pan on medium heat and add oil.
When hot, add the cumin seeds and cook them until the spluttering stops.
Add the onions and fry until soft and translucent.
Add the garlic and the ginger and fry for 1 minute.
Add the tomato and all the powdered spices.
Add 1/2 cup of the vegetable stock and let simmer, stirring occasionally, until most of the liquid is gone.
Add the eggplant and remaining 1/2 cup of stock and mix well. Put a lid on the pan.
Simmer, cooking down until most of the liquid is gone. Stir occasionally so that it doesn't stick to the bottom.
Remove the lid, add the butter and lime juice, stir to mix and serve.
Garnish with the cilantro before serving.