Tuna Fish with Sweet-Sour Onion Sauce 


“Tonno con Cipolla Agro-Dolce” 

 “Tunnina Cipuddata ca’ Acitu” 


In Sicily, tuna fish is very abundant from the month of May to the end of June. 

Tuna is boiled in big chunks and preserved in oil and stored for the winter months. 

At this time of the year, or when fresh tuna is available, a well-liked dish is tuna fish with sweet-sour onion sauce. It is very tasty, very convenient because it can be kept refrigerated for a few days, and mostly because it is very appetizing and delicious. 

Sweet-sour sauce was a traditional way of cooking in the Jewish households to preserve food for the Sabbath, when cooking was prohibited.  

Up until the year 1492, prior to the Spanish occupation of Sicily, a large colony of Jewish people lived there and prospered in the commerce of exporting Sicilian products, in many types of manufacturing and in retailing.  

This practice of cooking with wine and honey, and later with sugar, was applied in the preparation of meat dishes and vegetables and after the Jewish communities left the Island, this practice was expanded to become part of the conventional Sicilian cuisine. 

Some of the jewels and well known dishes of sweet-sour Sicilian cooking and part of this site are: 

Caponatina – Eggplant Salad 

Cucuzza C’acitu – Sweet-sour Squash 

Ficatu Agru e duci – Liver in Sweet-sour Sauce 

Pisci ‘ncipuddatu – Fried Fish covered with Onion-vinegar Sauce 


At Joe’s of Avenue “U”, the Focacceria Palermitana, we occasionally cooked this special and delicious tuna fish in sweet-sour sauce: it had a sweet and pungent taste, it was sprinkled with toasted pine nuts and raisins and we served it with a side dish of caponatina.  




  • 4 slices of tuna fish, 6 oz. each  
  • ½ cup of oil for frying  
  • ¼ cup of olive oil  
  • 3 large onions thinly sliced  
  • 2 stems of fresh mint or ½ teaspoon of dry mint  
  • ½ cup of vinegar  
  • 1 full tablespoon of sugar  
  • Salt and pepper to taste  
  • Few sprigs of mint for garnish  
  • 4 tablespoons of lemon juice (optional)  




Optional Preparation for Cooking the Tuna

To eliminate some of the blood from the flesh of the tuna fish in order to enhance and improve its taste, flavor and appearance, place the tuna in a glass or stainless-steel container and barely cover it with water, add 4 tablespoons of lemon juice, a pinch of salt and keep in this marinade for a few hours.

Or just keep in cold lightly salted water for a few minutes.

Before cooking rinse the fish in running water, place in a colander and drain for a few minutes. Gently pat dry well with a clean dish towel or paper towels. 


The Tuna Fish
In a large skillet (12 ½ inch wide) place the ½ cup of frying oil and over a high heat fry the slices of tuna fish cooking it 2 ½ minutes on each side. Fry the tuna 2 slices at a time and use a large spatula when turning it; set aside in a large plate and sprinkle with some salt. 


The Sauce
Discard frying oil and in the same skillet, over a medium heat place ¼ cup of olive oil and the sliced onions. Cook the onions for 5 to 7 minutes, until they are translucent, and start to get a light brown color. Add in the sugar, mint, a pinch of salt and pepper to taste. Increase the heat to high and add in the vinegar. Continue cooking until some of the vinegar has evaporated. 


The Assembly 
Lower the heat to a medium, place the tuna fish on top of the sauce and scoop some of it on the top. Cook until the vinegar evaporates, (1 or 2 minutes); taste the onion sauce and adjust for salt, and if needed add more sugar or vinegar to suit your taste. 

Place in a serving dish, scoop the onion sauce on top of the tuna fish and garnish with mint sprigs.