Prepare noodles per package directions. Divide into serving bowls.
In a large saucepan, bring broth and water to a boil. Whisk in miso paste. Add carrots and peas. Cover and cook over medium heat for 2 to 3 minutes. Stir in the shrimp. Cook for 1 minute. Stir in the soy sauce. Serve over noodles with garnishes.
Miso paste is a staple in Japanese cooking that transforms plain broth into restaurant-quality soup.