Ingredients:
1 kg small onions
100 grams sultanas
1 cup white vinegar
1/2 cup olive oil
2-3 tablespoons sugar

Sauce
400 grams tomatoes
2 onions, chopped
3 cloves garlic, minced
1 bouquet garni
sprig basil
1/4 cup olive oil

Directions:
Combine all the sauce ingredients and cook over medium heat for 30 minutes or until tender and pulpy. Remove bouquet garni. Pour sauce into a sieve and rub with a wooden spoon to extract as much liquid as possible.
Peel onions and place in a large heavy-based saucepan. Add the sauce, remaining ingredients and just enough water to cover the onions. Bring to the boil, stirring. Reduce heat and simmer uncovered for 1 hour or until onions are tender. Season to taste adding a little extra sugar to counteract the acidity.