600 gr eel
can of tomatoes,
salt and black pepper,
cut the fish in small pieces of 4-5 cm, clean and wash it.
In a pan add oil and enough sliced onion to cover the bottom, and cook it.
When it's golden, add the eel, vinegar and water to cover everything.
Add salt, pepper and tomatoes and let it simmer until the fish is soft.
Serve very hot with some polenta.