What you need:
-Block of wood
-Various sized forstner drill bits
-Drill or drill press
How to make it:
-Set your table saw to 25 degrees and make sure that the height of the blade is at least 1/2″ lower than the thickness of your wood. (Or you’ll cut completely through the wood and maybe chop off a finger while you’re at it… just overall not a good idea.)
-Run your block of wood through the table saw upside down, leaving about 1″ of wood behind where the mirror will go.
-Use various sized forstner bits to drill holes in front of where the mirror will go. Be careful not to drill too close to the slot cut for the mirror.
-Put mirror in the slot. Mine fit pretty securely but you can always put some glue into the slot before adding the mirror for some extra security.