Peel and wash rutabaga, carrots and potatoes. Dice rutabaga and potatoes, cut carrots into slices. Peel and chop onions. Heat oil in a large pot and fry half of the onions in it.
Add pork cheek and vegetables and season with salt and pepper. Add 3/4 - 1 litre of water, bring to the boil, cover and cook for about 1 hour. Remove pork cheek, place in the fat pan of the oven and roast in the preheated oven (electric cooker: 200 °C/ convection oven: 175 °C/ gas: level 3) for 25-30 minutes.
Drain the fat and set aside. Cut pork cheek into thin slices and put the slices back into the fat pan side by side. Brown under the preheated grill for 8-10 minutes until crispy, turning once.
Heat 2-3 tablespoons of the drained fat in a pan and fry the Nuremberg sausages in it. Remove and keep warm. Heat another 2-3 tablespoons of the fat in the pan and fry the remaining onions in it until golden brown.
Wash parsley, shake dry and chop. Heat turnip stew again and add butter. Use a potato masher to mash the potatoes until only a part of them remains chunky. Season to taste with salt and pepper.
Arrange turnip stew with grilled pork cheek and Nuremberg sausages in deep plates. Spread browned onions on top and sprinkle with parsley.