Preheat oven (electric cooker: 225°C/circulating air: 200°C/gas: level 4). Coat a baking tray with some oil. Clean and wash the aubergine and cut it into slices about 1 cm thick. Place them close together on the baking tray.
Season with a little salt and pepper. Bake in a hot oven for 20-30 minutes (do not turn!).
Peel and finely dice the onion and garlic. Heat 1 tsp. oil in a pot. Fry for 5-7 minutes until crumbly. Fry the onion and garlic briefly. Stir in chunky tomatoes, bring to the boil and simmer openly for 5-8 minutes.
Wash oregano, shake dry and chop. Stir into the sauce and season with salt and pepper.
Feta crumble. Remove the aubergine from the oven and remove the slices from the tray. Alternate with the feta on two plates and layer into turrets. Add the tomato sauce.