In a medium saucepan or pot, bring the chicken broth to a gentle simmer over medium heat. Stir in soy sauce, ground ginger, white pepper, and sesame oil if using. If you prefer a slightly thicker soup, mix the cornstarch with water to create a slurry and add it to the simmering broth, stirring well to avoid clumping.

In a small bowl, beat the eggs until well combined. Reduce the heat to low, then slowly drizzle the beaten eggs into the soup while stirring the broth gently in a circular motion with a ladle or fork. This will help create delicate egg ribbons instead of clumps.

Allow the soup to simmer for another minute, then remove from heat. Taste and adjust seasonings if needed. Ladle the soup into bowls and garnish with sliced green onions, a sprinkle of sesame seeds, and a drizzle of chili oil if desired.