Peel vegetables, dice and place in saucepan with enough water to just cover. Bring to a boil, cover the pan and simmer vegetables until tender. Drain the vegetables, reserving some of the cooking water. Mash vegetables, by hand or using a blender or food processor, with the milk, butter, cayenne and nutmeg. Add some of the reserved cooking water if needed to obtain the desired consistency. Garnish with the parsley or chives and serve.