Yaki Onigiri

1.In a small saucepan, add the mirin, sake, and sugar. Turn on the heat to medium and whisk all the ingredients together. Then, add the soy sauce and bring it to a boil.
2.Once boiling, reduce the heat to low and continue simmering for 10 minutes. Toward the end of cooking, you will see more bubbles. Turn off the heat and let it cool. The sauce will thicken as it cools.
3.In a rice cooker add rice and water. Cook until done, let the cooked rice cool a little bit until you can hold rice without burning your hands.
4.First, wet both of your hands with water so the rice won’t stick. Then put some salt in your hands and rub to spread all around.
5.Scoop about a half cup of rice onto your palm. If you have filling add the filling to the middle and cover with rice. Cover the rice with the other hand and gently form the rice into a triangle. Make sure the covering hand should be forming a triangle shape. When forming the onigiri shape, your hands should be just firm enough so the onigiri doesn't fall apart. You don't want to squeeze the rice too tight.
6.Use three fingers (thumb, index finger, middle finger) to cover the area to make a nice triangle shape. Then rotate onigiri to make a perfect triangle. While you squeeze onigiri firmly with both hands, one of your hands has to press onigiri to keep a nice form. Gently squeeze the center of the triangle on both sides so there is a slight indentation.
7.Lightly oil a cast-iron skillet and put it on medium heat. Grill onigiri until all sides are crispy and lightly browned. Rice will release itself when it forms a nice crust. Don’t flip it quickly. Just work on one side at a time and avoid turning over frequently.
8.Once all nicely toasted and lightly brown, lower heat to medium-low heat. Brush all sides with prepared sauce. Rotate to make sure all sides become crispy. Be careful not to burn onigiri after you brush it with the sauce.