Bring broth and garlic (if usinto a simmer over medium heat.
Break eggs into a cup with a spout (such as a Pyrex measuring cuand whisk together.
Vigorously whisk cornstarch into broth mixture.*
While stirring the broth mixture with one hand, slowly pour the whisked eggs into the pot with the other hand. Remove from heat and let stand 1-2 minutes.
For adult version: Garnish with green onions. For baby version: Strain some of the egg solids out of the broth before feeding.
*You could do this step properly and avoid lumps by removing some of the broth, stirring in the cornstarch to create a paste and returning the paste to the pot, but for this recipe, I've never found that it made much difference. Egg drop soup is lumpy anyway.
This recipe is easily scaled. Just add one additional cup of chicken broth / tsp of cornstarch / egg per serving.