Add 5 tbsp tempura flakes (tenkasu), 1 tbsp aonori (dried green seaweed powder), 1 tbsp Japanese soy sauce (koikuchi shoyu), ½ tsp sugar, ¼ tsp dashi granules, ¼ tsp toasted sesame oil, and ¼ tsp Chinese-style chicken bouillon powder to a large bowl.
Mix thoroughly until everything is evenly distributed.
Once all the liquid is absorbed, add 300 g cooked Japanese short-grain rice to the bowl and mix until the mixture is evenly spread through the rice.
Divide the rice into equal portions and shape. Refer to the 3 ways to shape onigiri article for advice on how to shape onigiri by hand, using plastic wrap, or a mold. But I really recommend shaping this one with a mold as the rice is oily and hard to shape by hand.
Enjoy!
Notes
Best eaten immediately. Rice balls for bento boxes should be wrapped with plastic wrap to prevent them from drying out and stored with an ice pack to keep them cool.
For storage, wrap individually in plastic wrap and store in a sealed container in the freezer for up to 1 month. Microwave to defrost.