For the Rösti with bacon and cheese, finely dice the bacon and heat in the butter. Cut onion into strips and sauté until translucent.
Coarsely grate potatoes, season with salt and pepper and add. Turn, form into a cake and fry until light brown on both sides. Five minutes before the end of the frying time, spread cheese over the rösti and let it melt.
Serve the rösti with bacon and cheese.