Put the contents of the bag into a bowl and knead with egg. Heat oil in a pan. Spread the roasting mixture evenly in it. Fry over medium heat for about 2 minutes, turning. Form a Rösti from the edge of the pan towards the middle and fry for 5-6 minutes. When a golden yellow crust has formed on the edge, turn the Rösti using a flat plate. Slide back into the pan and fry for another 5 minutes.
Drain the mozzarella and cut into slices. Wash and clean the tomato and also cut it into slices. Wash and clean the rocket and drain well. Top the Rösti with tomato and mozzarella. Cover and continue cooking for 1-2 minutes until the cheese has melted slightly. Season with salt and pepper and sprinkle with rocket