I've played around with a variety of recipes for butter mochi. In the travel section, under Ono Grinds, you'll find the recipe I have refined and use at home. Sometimes I also add some fresh lilikoi (passionfruit). It changes the texture a bit, but is delicious too. I've tried mango puree, but didn't care for that. I've seen some people add cocoa powder, tho that too changes the texture.
I make it in half batches in a 8x8 pan. But you can double the recipe and make it in a 9x12. It doesn't store long, but, in my house it doesn't last long either! At the end of the recipe I tell you how to best store it for a few days if you are able to control yourself and not eat the whole pan the first day.
I've played around with a variety of recipes and this is the recipe I have refined as perfect to my taste - crunchy edges, custard-y top and chewy mochi texture. Sometimes I also add some fresh lilikoi (passionfruit). It changes the texture a bit, but is delicious too.
I hope you give my recipe a try. And next time in Hilo, visit Two Ladies for an extra special box of Hilo style, Japanese mochi!
Aloha! And A hui hou!