Antipasto piemontese (preserved vegetable starter from Piedmont)

Method

1. 1 Wash the tomatoes and cook them in a frying pan, without water, with a little salt for 10 min. over a low heat and covered.
2. 2 Pass the tomatoes through the food mill and put the sauce you get into a separate pan.
3. 3 Once you have cleaned and washed them well, cut all the vegetables into fairly small pieces and put them in the pan with the tomato sauce, the oil, the salt, the sugar and the vinegar and boil for 45 min.
4. 4 At this point add the artichokes and the tuna and cook for another 5 minutes.
5. 5 Leave it to cool before bringing it to the table; if instead you want to keep a store of it, put it into the jars while still boiling hot.