I love Maangchi‘s original recipe from 2011, which is now available only on video now: https://youtu.be/WuNrLgh2Vw0?si=DgqBSTmaXmOdFyAt
The ingredients are: 1.5 cups chicken broth, 3 eggs + 1 egg yolk, 1 chopped scallion, and 1 tsp fish sauce. I use the smallest burner on my range to prevent the temperature from getting too high. I have to keep the heat at low-medium (for an murmuring boil) once I add the eggs) and often cook for an additional 2 mins on a very low simmer until it puffs up like a soufflé. (Sept. 2015).
Note: Sometimes a lot of broth remains as a pool rather than getting incorporated into the egg mixture. This can be due to either cooking on too high heat (so the eggs solidify too quickly) or not heating the broth enough before adding the egg mixture. It is a tricky balance to get the right heat level. I think it’s best to make sure the broth has come to a boil, then reduce to a small (but existent) murmur before swirling in the egg mixture. It’s also helpful to use the smallest burner on your range to mitigate overheating the broth (which will lead to an egg drop soup texture instead of steamed egg custard). Note 2: If too much broth is floating above the finished dish, sop up the liquid with a clean, dry paper towel before garnishing with toasted sesame oil.
Cooking Adventures 