Preheat the oven to 475°F/250°C
Place the eggplants in a large bowl with ¼ cup/60 ml of the oil, ¾ teaspoon salt, and a good grind of black pepper. Mix well, then spread out in a single layer on 1 or 2 baking sheets lined with parchment paper and roast in the oven for about 40 minutes, until golden brown and cooked through. Remove and set aside to cool
Meanwhile, put the chickpeas in a bowl along with the cumin seeds, lemon flesh, 3 tablespoons of the oil, 2 tablespoons of the cooking liquid, ½ teaspoon salt, and a good grind of black pepper. Mash roughly using a fork or potato masher, adding a bit more of the cooking liquid if needed to get a thick, spreadable paste
Place the yogurt in the bowl of a small food processor along with the remaining 1 tablespoon olive oil, 2 tablespoons water, the herbs, ¼ teaspoon salt, and some black pepper. Blitz until well combined. You need to be able to drizzle the yogurt, so add a tablespoon or two of water or oil if you need to
To arrange, spread the eggplant slices out on a platter or individual plates. Spoon the crushed chickpeas on top, followed by a drizzle of the yogurt, and serve