Step 1

Mix luke warm water and ¼ teaspoon dried dashi powder in a medium bowl. I use either katsuo dashi (bonito extract) or konbu dashi (seaweed extract). Add shoyu, mirin, and sugar. Add 4 eggs and gently mix using chopsticks. Try not to create too many bubbles.

Step 2

In a small bowl, add baby spinach, enough water to cover spinach and microwave on high for 30 seconds to 1 minute. Drain and run spinach under cold water until cool. Squeeze excess water from spinach, then chop. Combine spinach and egg mixture.

Step 3

Heat medium frying pan over medium heat and spray with cooking spray. I used a rectangular tamagoyaki pan for this, but I recommend using the simple "rolling over" method which is what I use for making Bebe E's hourensou tamagoyaki (see below).

Step 4

Pour a thin layer of the egg mixture into the pan and lower the heat to medium low. Allow the bottom to cook and become firm enough to fold over, about 3 minutes. If any large bubbles begin to form, use your chopsticks to gently pop the bubble.

Step 5

Gently fold over the egg from one end and keep going until you reach the end of the pan. With each fold, allow the egg to cook a little bit before creating the next fold.

Step 6

At this point, pour yet another thin layer of the egg mixture into the pan, gently lift your folded over layer to allow the wet mixture to seep under the cooked egg, and allow this to cook and become firm enough to fold over again. Now you'll fold your omelette back towards the opposite end of the pan from which you came.

Step 7

Repeat the previous step. I repeated this step twice more before I allowed the omelette to cook just a few more minutes in it's rolled state. You'll probably have some egg mixture leftover in order to make a second omelette, but this will depend on the size and type of pan you use.

Step 8

Remove tamagoyaki from pan and rest the tamagoyaki on a bamboo sushi rolling mat. You can skip this part, but if you're looking to impress, I recommend trying this because the sushi mat creates an interesting (and fancy) pattern on your tamagoyaki.

Step 9

While the tamagoyaki is warm (not hot off the stove), gently roll the tamagoyaki in the sushi mat and apply pressure to create a subtle pattern.

Step 10

Once the tamagoyaki is cool, slice to desired thickness and serve.