This is a classic simple side dish from Calabria, traditionally made with the oblong sweet red onions of Tropea, on the southwest coast not too far from the Straits of Messina.
The onions are sliced thinly and then braised in a mix of red wine and red wine vinegar with water until they are soft and mild.
- Cook the onions in the oil over moderate heat until they start to soften.
- Add the wine, vinegar, and water. When it comes to a simmer, reduce the heat and gently braise the onions until tender, about 20 minutes.
- Serve hot as a side dish with meat or fish.