Place the whole aubergines on a very hot grill, or directly on the embers if you prefer. Let them scorch all over, turning occasionally, until the skin is charred and the flesh is so soft that it seems they are going to collapse. While the aubergines are cooking, combine all the dressing ingredients apart from the chopped parsley. Separately mix the tahini paste with the water to form a thick whipped cream consistency. Once the aubergines are fully blackened, remove from the grill onto serving plates and slit open to reveal the flesh. Add the parsley to the dressing and mix well. Use half the dressing to douse the flesh of the slit aubergines, then top with the whipped tahini. Use the back of a spoon to create a little well in the tahini and place a raw egg yolk in the centre of each one. Using tongs, carefully remove a hot charcoal from the fire and lightly char the top of each yolk. Return the coal to the fire and drizzle the remaining dressing over the aubergines before serving.