Make the slurry by whisking together ½ cup of the chicken broth with cornstarch in a small bowl until smooth. Set aside.
Pour the remaining 5 ½ cups of the chicken broth in a medium pot over medium high heat. Add sesame oil, ginger, salt, pepper and garlic powder. Stir or whisk to combine and bring to a gentle simmer.
While the broth is reaching a simmer, whisk the eggs in a small bowl (or a measuring cup with a spout with a 2-cup capacity).
Once the broth has reached a simmer, use a large spoon or whisk to stir (or whisk) the broth in a circular motion (this will help the beaten eggs to form into "ribbons").
While stirring in a circular motion with one hand, use your other hand to slowly drizzle in the beaten eggs in a thin stream, while continuing to stir.
Add green onions and stir to combine.
Stir the cornstarch slurry you prepared earlier. Slowly pour in the cornstarch slurry and stir to combine. Bring back to a gentle simmer and remove from heat.
Season with additional salt and pepper, to taste. Serve topped with additional sliced green onions, if desired.