Clean, peel, and grate the apples on the bigger grating slots of a grater.
Mix the sour cream and horseradish, and stir with the apples and raisins, adding salt and pepper to taste. You can add some chopped walnuts for a crunchy texture.
Place the filling on each slice of ham, roll it, and fasten with a toothpick and tie with a cooked leaf of a leek.