Finely chop the onion, celery and garlic. Roughly chop the carrots.
Heat the oil in a pot, then sauté the onion & celery for 5 minutes. Add the garlic and stir for a minute. Add the tomato purée and marjoram, then the carrots. Stir for a minute, then pour over the stock.
Bring to a boil, cover and cook for 15-20 minutes until the carrot is tender, then add the mixed green leaves.
Turn off the heat, cover the pot with a lid and rest for 3 minutes.
Using a stick blender, process the soup until you get a lightly textured, creamy soup.
Stir in the vinegar and serve.