1 tbsp chopped chives (or parsley or dill)
800g/1lb 12oz new potatoes, cut into roughly 4cm/1陆in pieces
1 medium onion, finely chopped
1 tbsp Dijon mustard (or half English mustard)
150ml/5fl oz vegetable or chicken stock (made with half a stock cube)
salt and freshly ground black pepper
pinch freshly grated nutmeg
3 tbsp light olive oil
pinch sugar
2 tbsp white wine vinegar