Wash the potatoes and cook in boiling salted water for 15-20 minutes. Then rinse with cold water, peel and slice. In the meantime, clean, wash and slice the aubergine and sprinkle with salt. Wash and clean the zucchini and also cut them into slices. Grate cheese. Whisk eggs and milk. Season with salt and pepper.
Wash thyme, chop roughly. Put the potatoes, aubergines and zucchini in an ovenproof pan greased with olive oil, sprinkle with some cheese and thyme. Spread olives on top. Pour egg milk over it. Sprinkle with the remaining cheese and thyme. Let stand in the preheated oven (electric cooker: 200 °C/ gas: level 3) for about 20 minutes and serve