Cook the potatoes in salted water until almost ready. Dice the cooled and peeled potatoes. Dice the ham.
Dice the peeled onion, brown the onion in butter.
Add the onion to the ham, continue to fry in butter, and then add the potatoes, and fry a little. Sprinkle with salt and pepper.
Combine the fried potatoes, onion, and ham with sour cream. Put all the ingredients in a baking tin. Dust the top with grated cheese. Bake for 20-30 minutes in preheated to 180C oven.
It can be served both hot and cold. Dress with lettuce leaves.