Summer appetizer

Preparation:

Preparation: Boil the green beans in boiling salted water, after having trimmed them and freed them from any threads. Also boil the potatoes, already peeled, always in salted water. Boil the eggs, then let them cool. Drain the tuna from the oil, pit the olives and cut the tomatoes into slices. Now prepare the serving dish, preferably round, as follows: arrange the green beans in the center in a dome shape, surrounding them with the sliced potatoes, slightly overlapping each other; around the potatoes make a circle of anchovy fillets and around this, always round, the tomato slices (it would be better if the tomatoes were of the same size, so as to obtain fairly uniform slices); surround again with the slices of three hard-boiled eggs, placing a boned olive on each of these. Finally, sprinkle the chopped tuna all over. With the other hard-boiled egg, cut into wedges, decorate the green beans, forming a sort of star: place an olive in the centre. Put the mustard in a bowl, dilute it with the oil, add the lemon juice, a pinch of salt and a good pinch of pepper. Emulsify the sauce, beating it with a fork, and pour it over the vegetables just before serving them.