Yakionigiri, or grilled rice ball, to me, is for grown-ups. It's something you order in Izakaya restaurant (a sort of Japanese pub). After you have eaten, drunk and talked enough, in order to "finish" the dinner, you order a small rice or noodle dish; yaki-onigiri is one of such dishes.
When lightely grilled--over glowing coals, open flame, or in a frying pan--rice balls become crunchy on the outside, soft in the inside, and add the nice, roasted look and smokey flavor.
Yaki-onigiri is often seasoned with soy sauce, but miso is also used. You can just spread some miso over rice balls and grill them.
But today I made something even tastier: Negi-Miso, or Leek Miso. The leek, cooked slowly, becomes wonderfully sweet and flavorful; when you mix it with umami-packed miso, it turns into a versatile condiment that is perfect for yaki-onigiri.
I cooked the rice balls in a frying pan, but if you have a toaster oven, it's even easier--lightly oil a sheet of aluminum foil, place the rice balls, and just pop them into the heated toaster oven. This way, you don't need to turn the rice balls to cook all sides.
To make rice balls, the easiest way is to use a sheet of plastic wrap and a small bowl. With the plastic wrap, you don't need to worry about handling hot rice, or rice sticking to your hands, etc.
Although it used to be something that I would eat after drinking sake, yaki-onigiri is great for lunch as well. Prepare some green tea or roasted green tea, and buon appetito!
Negi-miso: Put the oil and sliced leek in a frying pan. Turn on the heat to low and cook, stirring constantly, until the leek wilts and gets reduced to about 1/3 (5 to 10 minutes). Turn off the heat, add miso and mix very well. Turn on the heat again (medium low) and heat for 1 minute or so, mixing. Turn off the heat and set aside.
Rice balls: Place a sheet of plastic wrap on a rice bowl (or any small bowl). Put about a half cup of rice on it, wrap it with the plastic wrap. Using both hands, make a triangular shape. Open the wrap. After you finish making the rice balls, spread the negi-miso on one side.
Heat a frying pan, lightely oil it, and cook the rice balls on medium low heat until the surface dries and has slightly golden color. You can cook only one side, or all sides (that do not have the negi-miso on). Lastly, cook the side with negi-miso about 10 seconds.