Peel jacket potatoes and cut into cubes. Peel and dice the onion. Cut the sausages into slices. Heat the butter and oil in a pan, fry the potato cubes in it. When they have taken on color, add onions, cucumber and sausages and fry for 10 minutes. Season everything with salt, pepper and marjoram. Fry the eggs in an extra pan with the fried eggs, season with salt. Before serving, cover the sausage pan with the eggs and sprinkle with chopped chives.