Build a small fire in the grill. Whe the coals are very hot, throw some grape vine or other fruit cuttings on them and place the eggplant right in the flames. Leave them there until the side touching the coals is black, which will take 8 to 10 minutes. Turn the eggplant and leave them on the fire until they are black all over, another 8 to 10 minutes. Remove the eggplant and let them sit until they are cool enough to handle, then scoop out all the flesh.

In a mortar, coarsely crush the garlic with the salt and the capers until you have a thick puree. Add the eggplant pulp and pound it until it is smooth and well blended with the other ingredients. Stir in the lemon juice, then add the egg yolk and stir with the mortar until the mixture is creamy and pale green. This all goes together very quickly.

Transfer the salad to a serving dish, then drizzle with the oil. Serve with toast.