Clean, wash and cut the spring onions into rings. Heat oil in a pan. Fry the potatoes for ten minutes, turning them several times until golden brown. Leek onions shortly before the end of the frying time
Season with salt and pepper. Mix crème fraîche and mustard. Season with salt and pepper. Wash the chives and cut into fine rolls. Put something aside for sprinkling. Stir the rest into the sauce.
Arrange the fried potatoes with the ham in aspic and the chives sauce on plates. Garnish with radishes. Sprinkle with the remaining chives.