Cook the rice in a rice cooker or according the the package instructions in a pot or donabe.
In a separate cup combine the raw egg, shoyu, and mirin. Mix well with chopsticks or a fork. Add to the rice and mix well to completely combine with the rice. Alternately, you can make a well in the rice and add it directly to the bowl, mix it well, and then mix it into the rice.
Let sit 5-10 minutes until thickened and you can eat it with chopsticks. Top with desired toppings and dig in! If you want to heat it back up, pop it in the microwave for about 30 seconds and then throw on your toppings!
Best served with a simple miso soup on the side for a truly authentic Japanese breakfast experience!