Preheat oven (electric cooker: 200 °C/circulating air: 175 °C/gas: see manufacturer). Peel and finely dice onions and garlic. Cut chillies lengthwise, remove seeds, wash and chop finely. Heat the oil in a pot.
Fry the onions, garlic and chilli in it. Add tomatoes, add oregano and simmer for 2-3 minutes.
Season tomato sauce with salt, pepper, sugar and possibly ouzo. Pour into an ovenproof dish. Crumble feta over it. Bake in a hot oven for 10-15 minutes. Flatbread tastes good with it.