Wash the potatoes, wrap in aluminium foil and cook in the preheated oven (electric cooker: 200 °C/ convection oven: 175 °C/ gas: level 3) for approx. 1 hour. In the meantime, cut the Pommern-Spiess into fine strips and the gherkins into slices.
Peel onion and cut into fine rings. Wash and halve the tomatoes. Wash chives, shake dry and, except for a few stalks for garnishing, cut into fine rolls. Mix salad cream, yoghurt, mustard and chives.
Season to taste with salt and pepper. Mix the meat strips, gherkin slices, onion rings and tomatoes with the cream. Cover and put in a cool place. Let the potatoes cool down a little, cut them open a little and add the meat salad.
Serve garnished with chives.