You can use usukuchi soy sauce in place of the shiro-dashi. Please add in stock granules if you do so.
In a bowl, mix all the ingredients, and pour into a pan coated with oil.
Use cooking chopsticks to stir the mixture. Roll it up all at once once it looks like the photo above.
After rolling, (don't worry about shaping it!) add in 1 tablespoon of water (not listed in the ingredients) in a circular motion around the pan, turn off the heat, and immediately cover with a lid.
Steam cook in residual heat for about 3 minutes.
Cut off a big sheet of plastic wrap, wrap up the tamagoyaki tightly. This will help shape it up nicely!
You can also roll it up in a bamboo sushi mat as shown above.
It will be ready in about 5 -10 minutes! Remove the wrap, and cut it into approximate sizes!
When storing, once it has cooled, put it in a plastic bag still in the plastic wrap, and chill in the fridge (the water content will leak out).
Story Behind this Recipe
I just really wanted to make a soft tamagoyaki like the ones served at Japanese restaurants!
My tip is to roll it up quickly once it is half-cooked; then steam-cook, and wrap in plastic wrap. In the cooler seasons, you can cut it into approximate serving sizes, store the pieces in a plastic container and it's convenient for making bentos. Adjust the flavoring to your tastes!