In a medium bowl, place chocolate, butter, and salt. Melt in the microwave in 30 second bursts, stirring after each burst. When the chocolate mixture is almost melted, stir until completely melted and smooth. Add the powdered sugar and stir to combine. Place red wine in a small pot and boil. Add boiling wine to chocolate mixture and stir until smooth. Let glaze thicken for 4-5 minutes and while the cake is still in the pan, pour onto cake. Smooth glaze with an offset spatula. Place cake in the refrigerator for 1 hour or until the glaze is firm. Serve at room temperature.