Light the barbecue. Meanwhile, sprinkle the aubergine slices on both sides with 1 tbsp of salt. Allow to drain in a colander or sieve for 30 minutes, then rinse and pat dry.
To make the salsa, put the onion slices over direct heat on the barbecue (skewering them first will make them more stable) and cook for 8 minutes or until lightly charred on both sides. Finely chop and mix with the other salsa ingredients, plus some salt and pepper. Set aside.
Combine the molasses, cumin, cinnamon, aleppo pepper, sumac and olive oil, and mix to a paste. Brush evenly over the aubergine slices and thread them, concertina style, onto six skewers, packing them quite tightly.
Cook on the barbecue for 15-20 minutes, turning occasionally, or until soft and lightly charred. Serve with the onion salsa, herby couscous and yogurt.