Roasted Aubergine with fried onion and chopped lemon

2 large aubergines, halved lengthways with the stem on, 150ml olive oil, Salt and black pepper, 4 onions, peeled and thinly sliced, 1½ tsp ground cumin, 1 tsp sumac, 1½ green chillies, deseeded and chopped, 50g feta, broken into large chunks, 1 medium lemon, 1 garlic clove, peeled and crushed

Heat the oven to 200C/400F/gas mark 6. Score a crisscross over the cut sides of the aubergines, brush with 100ml of oil and sprinkle liberally with salt and pepper. Place cut side up on a baking tray and roast for 45 minutes, until golden-brown.
Meanwhile, pour the remaining oil into a frying pan over high heat, add the onions and half a teaspoon of salt, and cook for eight minutes, stirring, until parts of the onion go dark and crisp. Add the cumin, sumac and one chilli, cook for two minutes, then add the feta, cook for a minute, then turn off the heat.
Cut the skin and pith off the lemon. Chop the flesh, discard the seeds, and put in a bowl with any juices, the remaining chilli and the garlic.
The moment the aubergines are done, spoon the lemony sauce over the flesh side. Warm up the onions, spoon on top and serve warm or at room temperature.