Onions peel, halve and in strips cut. Heat the oil in a large pot. Fry the goulash in it on all sides for about 5 minutes. Season with salt and pepper.
Add the onions and fry for 3 minutes. Stir in tomato paste and bay leaf. Add vegetable stock while stirring. Stew meat for about 50 minutes in a closed pot at medium heat. Wash the peppers, dab dry, quarter, core and cut into strips.
Add the sauerkraut and peppers to the pot and braise for another 30 minutes. Wash, peel and chop the potatoes. Cook potatoes in salted water for about 20 minutes. Drain potatoes. Add milk and fat and mash to a puree.
Season to taste with salt and nutmeg. Stir sour cream until smooth and add to the goulash. Season goulash with caraway seeds, paprika and salt and arrange on plates with puree. Decorate with parsley leaves and dust with paprika powder.