Nothing could be easier: put a little rice in the bottom, mango in the middle, more rice on top.
|Cover and press,|
and this is what you get!
The rice I made turned out not so good. I think I skimped too much on the liquid. But the mango was super-ripe and juicy, so I made several onigiri that were mostly mango with just a little rice top and bottom.
I thought they were very tasty. Sophie thinks they'd be better with meat. I'll try that next. Maybe with spam!