Combine cream, vanilla extract, and salt together in a saucepan; bring to a boil. Stir wine into cream mixture and remove from heat.
Stir semisweet chocolate into cream mixture until completely melted. Stir butter into mixture until incorporated. Pour chocolate mixture into a container, cover with plastic wrap, and refrigerate until firm, at least 2 hours.
Line 2 baking sheets with parchment paper.
Scoop the chocolate mixture using a teaspoon or a melon baller and shape into 1-inch balls. Place balls on the prepared baking sheets and refrigerate for 10 minutes.
Remove from refrigerator and roll balls in cocoa powder to coat.