Cut aubergines into thick slices. Place in a bowl with water to cover. Salt and leave them for 30 minutes. Mix onion with garlic, tomatoes, parsley, salt and pepper. Drain and dry aubergines. Place in a clay pan with a lid and spread the onion mixture over them.
Pour over the oil, lemon juice and a little water. Cover with aluminium foil and then the lid and bake at 200oC for one hour until most of the liquid has been absorbed. Allow to cool before serving. Garnish with pieces of feta cheese.