Peel and grate the potatoes. Mix in a bowl with the salt and pepper and squeeze out any water,
Heat half the butter and oil in a 18-cm frying pan on medium heat. Add half the potato mixture and press flat.
Fry for 3 minutes with the lid on, then flip the rösti and cook the other side for 3 minutes with the lid on. Then, remove the lid and cook for a further 4 minutes on each side to get the top and bottom golden brown.
Keep the rösti somewhere warm (in a low-temperature oven or wrapped in a tea towel) and repeat for the second rösti.
Serve with the Graved style sea salad, fresh dill and vegan salmon-style slices!