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Have you taken classes with her yet?  These issues are usually covered.

You can "booby trap" the counter, with upside down mousetraps, scat mats, or some other means that the dog will not connect with YOU.
That way, she figures the counter is a dangerous place, and won't go there even when you are not home or watching.
To make a booby trap, you can fill a bunch of aluminum cans with some pennies and tape the tops.  Put them in a cardboard tray and attach a string.  Set the thing in a cupboard, leave the room taking the string with you.  (leave some harmless food on the counter)  When the dog takes the first steps (if she gets the food, it's too late) toward the counter, yank the string.  (Don't make eye contact, make sure the dog doesn't see you do it, and don't speak to the dog afterward).

We have taken puppy classes and she is a very well behaved dog with these few exceptions.  I have tried to "booby trap the counter and she didn't seem to care as long as she gets a treat she is happy.