Dumpling Soup

4 cups low-sodium chicken broth

1/4 pound thick-sliced ham, diced

2 tablespoons dry sherry or Chinese rice wine

1 tablespoon sugar

1 1-inch piece ginger, peeled and thinly sliced

4 3-inch strips orange zest

Kosher salt and freshly ground pepper

2 scallions, sliced, white and green parts separated

1 cup sliced button mushrooms

2 medium carrots, thinly sliced

2 to 3 napa cabbage leaves, thinly sliced

24 frozen chicken or vegetable dumplings or pot stickers Soy sauce, for drizzling (optional)