Clean, wash and cut the aubergine into slices of about 1 cm thick. Grate parmesan finely and mix with breadcrumbs. Whisk the egg in a deep plate. First pull the egg through the aubergine slices one after the other, then turn them in the Parmesan mixture.
Tap lightly. Heat the oil in portions in a frying pan. Fry the aubergine slices on both sides for 3-5 minutes. Take out and drain on kitchen paper. Do the same with the remaining aubergine slices.
Roast bread in a preheated oven (electric cooker: 200 °C/ circulating air: 175 °C/ gas: see manufacturer) for about 10 minutes.
In the meantime clean, wash and slice the tomatoes. Clean, wash and slice the zucchini lengthwise into thin strips with a peeler. Wash the rocket thoroughly and drain well.
Wash basil, shake dry, pluck leaves and chop finely. Mix mayonnaise and basil. Season to taste with salt, pepper and lemon juice. Remove bread from the oven and cut into 4 pieces.
Cut open lengthwise in each case. Spread a little mayonnaise on each half of the bread. Place aubergine, tomatoes, zucchini and rocket in layers on each underside of the bread. Place the bread halves on top and secure with wooden sticks.
Add the rest of the mayonnaise.