The ones we have around here get massive! Like.. the size of a rugby ball or larger. I cut them into slices about 1 inch wide...aka... 3cm or so. Just like you'd find a good steak. And we cook them the same way as a steak. By far my most prized and favorite edible mushrooms!
Supposedly there are some around here too! Hope to find some, I would love to throw them on the grill!