Place the sausage links in a small pot and cover them with water. Bring to a boil, then lower the heat to medium-low. Simmer for 10 to 15 minutes until no longer pink inside, then drain and slice.
Peel the potatoes and carrots, then cut them into even cubes. Finely chop the onions and trim the leek. Wash the leek well, because dirt loves to hide between its layers.
Warm the vegetable oil in a large pot over medium heat. Add the potatoes, carrots, onions, and leek. Stir well so every piece gets a light coating of oil.
Dissolve the bouillon cubes in hot water. Pour the liquid into the pot and stir gently. The vegetables should be well covered by the liquid.
Add salt, black pepper, marjoram, paprika, and nutmeg. Stir until the spices spread evenly through the pot. Bring everything to a boil so the flavors start to mingle.
Lower the heat, cover the pot, and let it cook gently. After about 30 minutes, the carrots should be tender. Give the soup a stir now and then so nothing sticks.
Stir in the sliced sausage, parsley, and chives. Let the soup simmer for about 5 more minutes. This short time lets the herbs and meat flavor the broth.
Take the pot off the heat and let it rest for a few minutes. Taste it and adjust the salt and pepper. Ladle the soup into warm bowls and serve right away.