Ingredients
Method
1.Place oil in a large saucepan and gently cook garlic, celery and onion until tender.
2.Peel and roughly chop the kumara, then add to the pan along with chicken stock, and season with salt.
3.Bring to the boil, then simmer until kumara is tender. Add most of the watercress, setting aside a few leaves to garnish. Cook for a further 5 minutes.
4.Blend soup in batches in a blender or food processor, then return to pan. Check flavours and season as needed. If too thick, dilute with more stock.
5.Serve soup in bowls, each with a dollop of sour cream and a few leaves of watercress.
