Melt the butter in a large saucepan over a low heat and cook the onion, leek and garlic for 10
minutes, or until very soft but not browned.
Add the carrot and potato and cook for 5 minutes. Add the stock and bring up to simmering
Add the tomatoes and tomato puree and season to taste with salt and pepper. Simmer for 15
minutes until the vegetables are very soft. Add the milk and warm through, then transfer the soup
to a blender or food processor and process until very smooth. You can pass the soup through a sieve
at this stage, if you like.
Return the soup to the rinsed-out saucepan and reheat gently. Garnish the soup with snipped
chives, if desired, and serve with granary rolls.