Combine a beaten egg, 1 cup chopped ham, 1/2 cup shredded Swiss or Jarlsberg cheese, some chopped onions and rosemary, salt and pepper to taste. Stir in 4 cups frozen hash brown potatoes. Heat 1 tablespoon oil in a 10″ non-stick skillet over medium heat. Pat the potato mixture into an even round in the pan. Cook until golden, about 5-6 minutes.
Remove the pan from the heat. Place a non-rimmed cookie sheet on top and, using potholders, flip the rosti onto the cookie sheet.
As you can see, for some reason it stuck to the pan. Maybe a non-stick skillet would work better. Return the skillet to the stove and heat another tablespoon of oil. Then carefully slide the rosti back in and cook for a couple more minutes.
Top with another 1/2 cup of Swiss cheese and cover for a couple of minutes until it melts. Then serve!