Wash the potatoes thoroughly, peel them, and slice thinly.
Melt butter in a pan and stir-fry the potatoes until cooked.
Flatten the potatoes evenly on the bottom of the pan.
Top with tomato sauce, chopped ham, bell pepper, and onion.
Sprinkle mozzarella cheese evenly.
Cover the pan and cook over low heat until the cheese melts.
Cut the finished pizza into bite-sized pieces and transfer to a plate.