Spread the Rösti on a baking tray of the oven and bake in the preheated oven (electric oven: 200 °C/ gas: level 3) for 15-20 minutes. Peel and finely dice the onions. Clean and wash the leek and cut into fine rings. Drain mushrooms on a sieve. Cut cucumbers into thin slices, ham into fine strips.
Heat oil in a large pan. Brown the mushrooms in it. Add onions and leek and fry briefly. Deglaze with wine, stock and cream. Bring everything to the boil and cook for 4 minutes. Stir in sauce thickener and bring to the boil. Season to taste with salt and pepper. Fold in cucumber and ham and heat it up. Arrange the shredded meat with the hash browns on plates.
Bring everything to the boil and cook for 4 minutes. Stir in sauce thickener and bring to the boil. Season to taste with salt and pepper. Fold in cucumber and ham and heat it up. Arrange the shredded meat with the hash browns on plates. Garnish with parsley