Re: Granite counter outside kitchen pass-thru window
I looked into a similar issue for cantilevering a granite top out over bar stools. We didn't want any brackets or corbels to knock knees on.
Have you considered steel "L" installed in the block? If the block is hollow and not to deep to the footer you could grout them in with concrete. A nice added touch is to route the underside of the shelf to accept the horizontal part of the bracket, making it invisible unless you crawled under the shelf.
Can correctly identify Shinola 3 out of 5 times*
*Under ideal conditions