Peel and wash the potatoes and cook them in boiling salted water for about 20 minutes. Peel the skin off the sausage. Cut the sausage into slices. Clean and halve the mushrooms. Peel and halve onions and cut into fine rings.
Peppers clean, wash and cut into fine cubes.
Heat the oil in a pan. Sear the mushrooms in it. Add the onions and peppers and fry them. Remove and put aside. Fry Weißwurst in the still hot frying fat while turning. Deglaze with broth.
Bring to the boil, stir in the sauce thickener and bring to the boil again. Add mushrooms, paprika and onions again. Season to taste with salt and pepper.
Drain the potatoes and let them drain well. Wash herbs, shake dry, pluck leaves from the stems. Chop parsley. Melt butter in a pan. Add the potatoes. Sprinkle with parsley and toss through.
Arrange goulash and potatoes on plates. Garnish goulash with marjoram leaves. Serve with coarse mustard.