Tomato sauce

• 50 g/1¾ oz/3½ tbsp unsalted butter
• 1

Melt the butter in a saucepan over a medium heat. Add the onion and celery and fry for 2 minutes. Add all the remaining ingredients and bring to the boil.

Turn the heat down to low and simmer for about 1 hour until rich and thick. Remove and discard the herbs, then leave to cool.

Store in an airtight container in the fridge for up to a week.