Combine the butter, wine, and confectioners sugar in a medium saucepan.
Gently bring to a boil, stirring occasionally, over medium-high heat.
Remove from heat; stir in vanilla.
Pour in chopped chocolate and stir to incorporate. Once chocolate glaze has cooled a bit (about 5 minutes), strain the glaze. (The easiest way to do that is place cheesecloth over top of a mason jar, press down for an indentation, then secure with a rubber band and pour.)
Remove cheesecloth and bits of chocolate and pour strained glaze over chocolate cake.