Peel, wash and roughly grate the potatoes. Squeeze a little, mix with egg yolk, flour and salt. Heat the oil in a large pan (with lid). Fry about 4 Rösti on both sides until golden brown.
Meanwhile cut ham and cheese in half. Wash the apples and cut out the cores with an apple corer. Cut apples into thick rings. Sprinkle with lemon juice immediately
Top the Rösti with apple rings, ham and cheese. Cover and fry for approx. 5 minutes until the cheese has melted. Garnish with cranberries and basil if desired
You can also bake the Rösti briefly in the preheated oven on the highest setting or under the grill. If you use pineapple rings (from a tin) instead of apple rings, you have delicious Rösti "Hawaii".