Heat the ghee in a large pot over medium heat. Place the lamb in the pot and cook until evenly brown. Season with allspice, cinnamon, cloves, nutmeg and cardamom.
Place a layer of onion on top of the lamb in the pot, followed by layers of potato, eggplant, zucchini and tomatoes. Do not stir. Place the chilli in the centre of the vegetables. Season with salt. Mix the tomato paste and water, and pour over the vegetables. Bring to a boil, reduce heat to low and simmer 1 hour, until vegetables are tender.
With a mortar and pestle, crush together the garlic, salt and mint. Mix with 2 tablespoons of liquid from the pot and pour over ingredients in pot. When removing the mixture to the serving dish - a fairly open or wide bowl - tip the pot and let it slide out the side so that it stays in the layers.