Peel garlic and chop very finely. Heat the oil in a large frying pan, add slices of bread and fry on both sides at low heat until golden brown. Shortly before the end of the roasting time, add garlic and marjoram.
Remove the slices of bread from the pan and put them aside. For the vinaigrette, mix vinegar, salt, pepper, sugar and mustard with the whisk of the hand mixer. Whip the olive oil into the vinaigrette bit by bit.
Clean and wash the rocket and drain well in a sieve. Clean, wash and roughly dice the tomatoes. Mix tomatoes, rocket, olives and slices of bread and arrange on four portion plates. Spread the vinaigrette evenly on top and serve garnished as desired with marjoram and parmesan slices.