Pour broth into a saucepan and bring to a simmer.
In a small bowl, mix the cornstarch with 1 Tbsp water until smooth.
Pour mixture into the broth while stirring.
Crack the eggs into a small bowl and beat lightly.
Pour eggs through a sieve into the broth while stirring (this will make nice delicate egg ribbons).
Remove from heat and stir in soy sauce and sesame oil.
Top with scallions and enjoy immediately!