Heat the oven to 200C/390F/gas 6, line a baking tray with greaseproof paper or foil and add the aubergine pieces. Drizzle in two tablespoons of oil, season, toss, spread in an even layer and roast for 25-30 minutes, until golden and dark at the edges.
While the aubergine is in the oven, fry the onion in the remaining two tablespoons of oil in a large pan over a medium heat, until golden. While it’s cooking, warm the cumin, coriander and allspice briefly in a small pan, then grind to a powder. Stir into the onions, along with the garlic, salt, cinnamon and paprika, and cook for a further three to four minutes to soften the raw flavour of the garlic and spices. Turn up the heat and add the lamb mince, seasoning well as it goes in the pan. Cook, breaking up the mince with a spoon, for seven to 10 minutes, until the lamb is cooked through.
Add the cooked aubergine to the lamb, stir in the pomegranate molasses, season, and cook gently for a few minutes to allow the flavours to mingle.
Drain and wash the chickpeas and then add and cook gently for a few minutes.
Take off the heat, stir in the pomegranate seeds and serve in toasted pitta breads.