I would completely clear the the counters for a couple of days of everything including my small appliances and bait them with stuff that's pre-sprayed with bitter apple, hot peppers or some other aversion flavored thing that he'll dislike. Then slowly put things back, just a couple of things at a time, spraying each one as you go--spray toaster, spray the bread box, etc. It shouldn't take long.
Karen taught her cats not to graze the counters with hot pepper spray; if a cat will learn by this method, a dog should pick it up in NO time!