1. Preheat the oven to 425F

2. Halve the eggplants lengthwise keeping the stem on. Score the cut side of each eggplant with a crisscross pattern. Brush the cut sides with 2/3 of the oil and sprinkle liberally with salt and pepper. Place on a baking sheet, cut side up, and roast in the oven for about 45 minutes, until the flesh is golden brown and completely cooked.

3. While the eggplants are roasting, thinly slice the onions. Crush the garlic. Add the remaining oil (1/3 of original amount) to a large frying pan and place over high heat. Add the onions and several pinches of salt and cook for 8 minutes, stirring often, so that parts of the onion get really dark and crisp. Seed and chop the chiles. Add the ground cumin, sumac, and 2/3 of the chopped chiles and cook for a further 2 minutes before adding the feta. Cook for a final minute, not stirring much, then remove from the heat.

4. Use a small serrated knife to remove the skin and pith of the lemon. Coarsely chop the flesh, discarding the seeds, and place the flesh and any juices in a bowl with the remaining chile and the garlic.

5. Assemble the dish as soon as the eggplants are ready. Transfer the roasted halves to a serving dish and spoon the lemon sauce over the flesh. Warm up the onions a little and spoon over. Can be served warm or at room temperature if you are done early