Bring the chicken or vegetable broth to a gentle boil in a pot.
In a small bowl, whisk the cornstarch with a bit of water until dissolved.
Slowly add the cornstarch mixture to the boiling broth while stirring.
Allow the broth to simmer for about 2 minutes until slightly thickened.
Reduce the heat to low to prevent boiling.
In another bowl, beat the eggs until well mixed.
Slowly drizzle the beaten eggs into the soup while stirring gently.
Add the soy sauce and sesame oil for flavor.
Season with salt and pepper to taste.
Garnish with chopped green onions and cilantro if desired. Serve hot!