Melt the butter in a wide pot (or pressure cooker.) When it has melted, add the olive oil. Add the spices and the garlic and cook and stir a minute or so. Add the eggplant, potatoes, peppers and chile, stirring the vegetables to coat them with the spices. Add the water (the lesser amount if using a pressure cooker,) and cover the pot. Simmer for 25 to 30 minutes (8 minutes for pressure cooker), stirring occasionally. Add the tomatoes. When the tomatoes are hot, serve the curry.