Haejangguk, Korean Hangover Soup

Name: Haejangguk, Korean Hangover Soup
Prep time: 15 min
Cook time: 45 min
Total time: 1 h
Cuisine: Asian, Korean
Ingredients: 10 cups water; 1 (5x5-inch) piece dried kombu, wiped; 4 dried shiitake mushrooms; 2 green onions, broken in half; 1 tablespoon red pepper flakes; 15 green outer napa cabbage leaves; 2 pounds beef chuck, cut into bite-sized pieces; 8 ounces mu (Korean radish); 3–4 green onions, cut into 2-inch pieces; 2–3 handfuls of soybean sprouts