Wash the Kasseler, dab dry and season with pepper. Peel and wash the potatoes and cut them into large pieces. Peel onion, cut into large pieces. Put potatoes and onion on a fat pan of the oven. Put the smoked pork loin on the bone on a grid and slide it over the meat. Cook in the preheated oven (electric cooker: 175 °C/ convection oven: 150 °C/ gas: level 2) for about 1 hour
Wash, quarter and core the apples. Roughly dice the apple pieces. Clean the fennel, cut into slices, cut off the stalks. Wash oregano, shake dry. Put some stalks aside for garnishing. Add apples, fennel and oregano to the fat pan. Season vegetables with salt and pepper. Pour 1/2 litre of water over the roast, finish cooking for another 20-30 minutes
Remove the roast and let it cool down a little. Take out bones, cut roast into slices, put back into the roaster and garnish with oregano