I've been seeing these baby portabellas in the grocery store for quite some time and never really bothered to try them, but that was until I saw some pics posted by Mike ("Lawn Ranger") where he just grilled them while he did steaks.  So I had to try them out.

Now, you can't get much more simple than this.  As Mike did, I marinated the shrooms in Italian salad dressing for, I don't know, maybe 10 - 15 minutes.  Then, I just threw them directly on the grate of my Mini, which I had going at about 450 degrees.  After about 5 minutes, I stirred them around a bit, then let them go another 5 minutes or so.

That's it!  And man are they delicious!