Cook 3 rice cooker cups of Japanese short-grain rice using a rice cooker or on the stovetop.
2
Transfer the hot cooked rice to a large bowl. Add 3 tablespoons soy sauce, 1 tablespoon toasted sesame oil, 1 tablespoon sugar, and 1/4 teaspoon kosher salt. Using a rice paddle with slicing motions, blend all seasonings evenly with the rice.
3
Moisten both hands with water. Scoop a handful of seasoned rice into one palm, place your other hand on top to form a mountain shape, and gently press the top corner. Rotate and continue pressing until a triangle shape forms, flattening the sides as needed.
4
Alternatively, if using an onigiri mold, soak it in water first. Fill the mold completely with rice, ensuring all corners are filled, cover with the lid, and press down firmly until you feel slight resistance. Flip the mold onto a baking sheet lined with parchment paper.
5
Place parchment paper on a large frying pan. Combine 1 tablespoon soy sauce with 1 teaspoon toasted sesame oil to make a glaze.
6
Moisten your fingers with water and gently place the rice balls on the parchment paper in the pan. Grill over medium-low heat until all sides are crispy and lightly browned.
7
Once browned on the bottom, flip the rice balls over. Brush them with the soy-sesame glaze, then flip again to brush the other side. Cook until both sides are nicely browned and crispy.
8
Transfer the finished yaki onigiri to a plate and serve warm.