50 gmbutter1leek, white part only, thinly sliced3onions, thinly sliced1stalk of young celery, thinly sliced1clove of garlic, crushed1 kgspunta or desiree potatoes, peeled, halved and thickly sliced1 litrechicken stock or water200 mlcrème fraîche1 tbsppressed lemon olive oil, plus extra, to serve100 gmbaby cavolo nero, washedTo serve:crusty bread
Melt butter in a large casserole or heavy-based saucepan, add leek, onion, celery and garlic and cook over low-medium heat for 5 minutes or until vegetables are tender but not coloured. Add potatoes, cover and cook for 10 minutes, then add enough stock to cover. Cook, covered, for 15 minutes or until potatoes are tender.
Purée soup in a blender until smooth, then pass through a fine sieve into a large saucepan and re-heat over low heat until warmed. Add crème fraîche and stir to combine, then season to taste with sea salt and freshly ground white pepper.
Heat lemon oil in a frying pan, add washed and still wet cavolo nero and cook until just wilted. Divide cavolo nero among serving dishes, ladle over soup and serve immediately, drizzled with a little extra lemon oil, and crusty bread passed separately.