Thickly slice the leek, and chop the aubergine, celery, and sweet potato into chunky bite size pieces. Cut the carrots and parsnips into thick batons.
Heat oil in a casserole or other suitable heavy based pan. Add the leek, aubergine, carrot celery and parsnips to the pan. Allow to caramelize slightly, stirring occasionally.
Using the flat side of the blade of a knife press down on the garlic cloves to crush slightly to make the papery skins easy to remove then drop these into the pot. Tumble in the sweet potato and using a micro plane mince in the ginger. Pour over the stock. Adding extra water until vegetables are just covered.
Bring to a boil. Then turn heat to low and put a lid on the pan, allow to simmer for 45 minutes or until vegetables are tender and liquid reduced slightly. When ready ladle into serving bowls and scatter with chopped parsley.