Authentic Homemade Pizza Sauce

Ingredients:
* 1 medium onion, finely chopped
* 2 tablespoons olive oil
* 500 grams can whole/chopped Italian plum tomatoes
* 2 teaspoons concentrated tomato puree
* 1 tablespoon white wine vinegar
* 3 teaspoons sugar

Directions:

In a large saucepan, gently saute the onion in the oil until transparent. Add the tomatoes and bring to the boil. Once simmering, add the tomato puree, the vinegar and sugar. Simmer for a full hour, using a wooden spoon to break up any tomato pieces. If the sauce still has pieces of tomato, pass through a sieve before bottling and storing in the refrigerator for up to two weeks. Spread thinly on pizza, use over pasta with a grated, strong, hard cheese, or use as a base for more complex meat sauces for pasta.