Chop the onion rings, apple - slices. Fry until golden brown. Push the onion and apple aside, melt the sugar on the freed space. Stir the contents of the pan, season with salt. The form of grease with butter, put a layer of Maultash. Top with a layer of caramelized onions with apple, sprinkle with cheese and bake in the oven at 180 degrees Celsius about 20 minutes, pepper and serve.