Finely dice the onions. Cut the sirloin into cubes and fry all over in oil in a pan. Take out, sauté the onions in the pan. Sprinkle with paprika powder.
Add the sauerkraut, sugar and vinegar to the pan. Simmer over medium heat for 5 minutes while stirring, put the smoked pork loin back in the pan and simmer for another 3 minutes. Season with salt and pepper.
In a second pan, froth the butter and fry the potato noodles in it. Mix the potato noodles with the cabbage and serve with a dollop of sour cream.