This is a popular soup in northern China. Cooking goes quickly, so you'll want to prep all the ingredients first. Simmering the soba noodles in the broth helps thicken the soup.
2 1/2 tablespoons grated peeled fresh ginger
2 tablespoons low-sodium soy sauce
1/4 teaspoon crushed red pepper
8 ounces flank steak, thinly sliced and cut into 1 1/2-inch lengths
2 large garlic cloves, minced
7 cups thinly sliced bok choy (about 1 pound)
1 cup thinly sliced shiitake mushrooms (about 2 ounces)
1 cup (1/4-inch-thick) slices carrot
1/2 cup thinly sliced green onions
2 cups hot water
2 tablespoons hoisin sauce
2 (14-ounce) cans less-sodium beef broth
4 ounces uncooked soba (buckwheat) noodles
1 tablespoon rice vinegar
1 1/2 teaspoons dark sesame oil, divided
How to Make It
Combine the first 5 ingredients in a large zip-top plastic bag, and seal. Marinate in refrigerator 2 1/2 hours, turning bag occasionally.
Heat a small Dutch oven over high heat. Coat pan with cooking spray. Add beef mixture to pan; stir-fry 1 minute or until browned. Remove beef mixture from pan; set aside.
Add bok choy, mushrooms, carrot, and green onions to pan; stir-fry 2 minutes or until bok choy begins to wilt. Add water, hoisin, and broth; bring to a boil. Stir in noodles. Reduce heat; simmer 5 minutes or until noodles are done. Stir in beef mixture and vinegar. Ladle 1 1/2 cups soup into each of 6 bowls; drizzle each serving with 1/4 teaspoon sesame oil.