In a large saucepan add chicken broth and heat over medium. When broth is warm remove ¼ cup and mix with cornstarch in a separate bowl until smooth. Add cornstarch slurry back into broth.
Stir in garlic, ginger, and sesame oil.
In a separate bowl beat eggs with a whisk.
Bring soup to a simmer. While whisking quickly, slowly pour eggs into simmering broth, creating thin ribbons of cooked egg in the soup.
Serve and top with thinly sliced green onions, crushed red pepper (if desired), add salt and pepper to taste.