Set up a bowl with a perforated tray or rack on top and lay a clean dish towel over it.
Using a sharp paring knife:Remove the tops of the aubergines as close to the tip as possible.Carefully slice halfway through each aubergine lengthways, creating an opening without cutting all the way through. Sprinkle a small pinch of rock salt inside the flesh of each aubergine. Place them on the dish towel opening side down.
Cover with another dish towel, then place a tray or plate on top large enough to cover them all. Add a heavy weight on top to press them down and draw out excess moisture. This step is key for getting that proper makdous texture.
Leave the aubergines to strain for 24 hours in a cool place.