Funnily enough I did this at the weekend.
A old sink filled with rotting logs.
Packing out the gaps with rotting leaf mould.
Then covered it all with compost.
I've planted wild strawberries on it but think I'll add white clover to fix nitrogen and the roots will help stabilise the soil.
I've been reading up on Hugelkultur for a while and this is a first attempt. I hope to build some decent size beds when I've got time. I only get to the land where this is every couple of weeks or so so I need something I can leave and not water, hence Hugelkultur.