Using a spice grinder or a mortar and pestle, grind the poppy seeds, cinnamon, mustard seeds, cumin, turmeric, cloves and peppercorns. (This may have to be done in two batches.) Grind the peanuts until they are quite fine but not oily. Mix the peanuts and spices together.

Preheat the oven to 350°F.

Melt the butter in a heavy stew pot over medium heat. Fry the spices and peanuts for several minutes, stirring constantly to prevent sticking, until their aroma is well-developed. Add the onion and salt, and cook for 5 minutes, stirring frequently. Pour in the water and bring to a boil. Add the eggplant 4 cups at a time, stirring each batch well to coat it with the liquid. Reduce the heat to low, cover the pot and let the eggplant cook until it is very soft, about 45 minutes. Stir and scrape the bottom of the pot frequently to prevent burning and ensure that the eggplant cooks evenly. Toward the end of the cooking time, remove the lid so that the stew may thicken further.

Once the stew is going well, spread the coconut over a baking sheet and let it toast in the preheated oven for 5-10 minutes, stirring once or twice, until it is brown and fragrant. Remove from the oven and put into a serving dish. Serve the stew over rice, garnished with coconut.