Peel, wash and coarsely grate the potatoes. Drain the sauerkraut, squeeze well and add to the potatoes together with the egg and flour. Season with salt, pepper and sugar and mix everything well.
Heat the oil in a frying pan. Add two heaped tablespoons of the potato and sauerkraut mixture to the pan, flatten and fry over medium heat for 3-4 minutes on each side until golden brown. Mix crème fraîche and lemon juice and season with salt and pepper.
Arrange the buffer and salmon on a plate and serve garnished with dill and dill flowers as desired. Serve with the crème fraîche dip.