Preheat oven to 375° F and grease a 9" round cake pan (I use additional butter for this).
Melt butter and chocolate in a small saucepan over low heat, stirring constantly until smooth.
Remove from heat and transfer to a mixing bowl.
Stir in sugar and salt.
Add the eggs till combined.
Stir in cocoa powder, then mix in the red wine till fully combined.
Pour the batter into greased cake pan and bake for about 25 minutes.
Cool the cake in the pan for 5-10 minutes, then flip out onto a plate, and flip from the plate onto a cooling rack (this keeps the top of the cake smooth and shiny).
Cool completely and enjoy!