When I was a small child living in Nakamichi, Japan my favorite thing to eat was yaki onigiri. (which translates to grilled triangular shaped rice) However as much as I love all Japanese food, there are exceptions which include Umeboshi (pickled plums), which resulted in my (spanish) mother replacing the filling of my yaki onigiris with olives. This only resulted in it becoming more delicious, which proves that growing up ethnically confused results in some delicious cross cultural food combinations. Sadly because I no longer live in Japan, I do not have a very tiny but powerful broiler right underneath the stove, although I didn't have an oven back then making cake baking pretty impossible. —Elisa
Wash and rinse the rice. Then either place in the rice cooker and follow cooker's instructions or cook on the stove, on very low heat, covered for 45 minutes.
Let cooked rice cool slightly, then you can either use your hands, or use a onigiri mold. (which is a lot easier)
Loosely pack the rice all the way to the top of the onigiri mold, then place olive in center and push down into the onigiri. Or use hands to shape rice into a triangle shape, then add olive.
Add more rice on top of the olive, then take the top piece of the mold and push as hard as possible, compacting the rice around the olive
If you have a proper broiler, brush the onigiri with olive oil and place under the broiler until golden brown and crispy. Then flip and repeat on the other side. Or if you don't have a good broiler, brush onigiri with olive oil and place in a preheated non-stick pan and cook until golden brown and crispy