In a large pan melt the butter and oil. Add the chopped onion, celery and garlic and sweat for about 8 minutes under a lid on a lowish heat. Stir occasionally until softened.
Increase the heat, add the carrots and stir constantly for about 2 minutes.
Add the vegetable stock, bring to the boil, then lower heat and simmer with a lid on for about 10 minutes or until the carrots are tender.
Add the parsley and simmer for another minute until wilted.
Pour in the milk and blend until smooth with a hand blender (or cool a little and pop into a liquidiser).
Reheat and season if wished (we didn’t find it necessary).
Serve with a garnish or garlic croutons and parsley if wished and plenty of crusty bread for dipping.