Cut the anago into 1cm slices, place in a microwave-safe container, cover loosely with plastic wrap, and microwave at 600W for 1 minute.

Crack the egg into a bowl, add salt and sake, and mix well.

Heat a frying pan with salad oil spread thinly using a paper towel. Pour in the egg mixture and cook over medium heat to make a thin omelet. Let it cool and slice into thin strips (kinshi tamago).

In a pot, combine the broth ingredients (dashi powder, soy sauce, and water) and bring to a boil.