Place the cabbage, carrots, beans, potatoes, the fresh peas, if using, the broth, salt, pepper, and nutmeg in a large heavy kettle (pot). Set over moderate heat and bring to a boil. Adjust the heat so the broth bubbles gently, cover, and cook without stirring for 20 minutes. Add the caraway seeds, marjoram, knockwurst, and frozen peas, if using, and toss lightly to mix. Re-cover and simmer 10 minutes. Add the parsley, toss lightly, and serve in soup plates with crusty chunks of bread.