Cooked Tomato and Parma Ham Sauce

• 1.7 kg/3¾ lb tomatoes, peeled, seeded and chopped
• 1 tablespoon finely chopped o

Fry the onion in the olive oil, add the Parma ham, thyme and bay leaf. Remove the pan from the heat and stir in 1 tablespoon of flour, return the pan to the heat and cook gently for 3 minutes. Add the tomatoes, season with salt, pepper and sugar and cook for 45 minutes, stirring from time to time.</