I have a bar nook area that I want to do something similar to the image below, but on the back of the shelves I want to put a large mirror. I was planning on ordering a custom cut mirror for the wall and then I want to install these floating shelves.

How do I get shelves without brackets showing on the sides? I also assume I can't put brackets that drill into the back of the wall because there will be a mirror there and it will crack.