Vietnamese Beef Soup

10 cups canned beef broth

2 medium onion s, thickly sliced

4 1/2-inch-thick slices fresh ginger (about 1 1/4 ounces)

2 tablespoons fish sauce (nam pla)*

3 large garlic cloves, halved

2 star anise

1 1/2 teaspoons whole clove s

1 pound flank steak , trimmed, thinly sliced crosswise

1 head romaine lettuce, thinly sliced

3 green onion s, thinly sliced

Lemon wedges

Bean thread noodles (clear dried noodles, also known as cellophane or transparent noodles), fish sauce (nam pla) and star anise are sold at Asian markets and in the Asian section of some supermarkets.