1 crispy lettuce , washed, dried and torn into pieces4 large tomatoes, sliced900 g. 2 lb potatoes, boiled in their skins, peeled, then quartered or sliced2-3 hard-boiled eggs, quartered1 onion, sliced into ringsHandful black or green pitted olivesLemon wedge, to serveSprinkling of fresh chopped parsley, to serveOlive oilVinegarSea salt