Method

1. Mix all the ingredients in a wide, shallow, ovenproof dish. Leave to marinate for up to 24 hours (this isn't absolutely essential, but it does allow the juices of the tomato to flow out and mingle with the oil and vinegar).

2. Pre-heat the oven to 150°C/gas 2. Roast the tomato salad in the oven for about 3-4 hours, stirring occasionally, until the tomatoes have reduced to a concentrated brick coloured mass. Cool slightly and then rub through a sieve and discard any debris of seeds, skin and herbs that is left.

3. Heat the sauce until boiling and then draw off the heat; spoon in to hot, sterilised jam jars.

4. Pour a little extra olive oil over the surface of each one and then seal tightly, label and set aside to cool down. Store in a cool, dark cupboard or in the fridge.