Chicken & Bok Choy Soup with Ginger & Mushrooms

Name: Chicken & Bok Choy Soup with Ginger & Mushrooms
Prep time: 30 min
Cook time: 30 min
Total time: 1 h
Cuisine: Asian, American
Ingredients: 1/2 ounce (about 1/2 cup) dried shiitake or mixed dried mushrooms; 3 cups boiling water; 1 tablespoon peanut oil or canola oil; 2 cups diced onion; 3 cloves garlic, thinly sliced; 6 1/8-inch-thick slices peeled fresh ginger; 6 cups reduced-sodium chicken broth; 0.25 cup reduced-sodium soy sauce; 1 2-to-3-inch cinnamon stick; 1 whole star anise; 1 teaspoon freshly ground pepper; 2 pounds boneless, skinless chicken thighs, trimmed and cut into 1-inch pieces; 1 bulb fennel, cored and cut into 1-inch pieces; 8 scallions, whites cut into 2-inch pieces and greens chopped, divided; 1 pound bok choy, preferably baby bok choy, white stems sliced lengthwise and greens chopped, divided; 2 cups (4 ounces) mung bean sprouts (see Note); 0.5 cup chopped fresh cilantro; 2 teaspoons toasted sesame oil; Lime wedges for garnish