"Packed with vegetables and sausages, this classic Bavarian-style potato soup is more of a main dish than a starter. In Germany the sausage of choice would be Regensburg sausage, a short and stubby parboiled pork sausage. It can be substituted with other boiling sausages made of pork."
Place sausages in a small pot and cover with water; bring to a boil. Reduce heat to medium-low and simmer until no longer pink in the center, 10 to 15 minutes. Drain. Cut into slices.
Heat oil in a large pot over medium heat. Cook potatoes in the hot oil, stirring often, until they start to crisp on the edges, about 8 minutes. Stir in carrots, onions, leek, scallions, and garlic.
Dissolve vegetable bouillon in hot water; pour into the pot. Season soup with salt, black pepper, marjoram, paprika, and nutmeg. Bring to a boil; reduce the heat and cook, covered, until carrots are tender, about 30 minutes.
Stir sausage slices, parsley, and chives into the soup. Simmer until flavors combine, about 5 minutes. Stir in sour cream just before serving.