In a small saucepan, heat the butter and wine together until melted and barely simmering. Remove from heat and whisk in cocoa powder until smooth. Set aside.
In a medium mixing bowl, whisk together flour, sugar, baking powder, and salt until uniform.
In a large mixing bowl, stir together sour cream and eggs until smooth.
Add the wine-butter mixture to the eggs, and then the dry ingredients, stirring until smooth after each addition.
Transfer batter into a prepared 9-inch round pan, or 5 prepared ramekins.
Bake for 40-50 minutes for the round pan, 25-28 minutes for the ramekins.
For the Ganache:
Chop 12 ounces dark chocolate, place in a medium bowl. Set aside.
Bring the heavy cream and wine to a boil in a small saucepan over medium heat.
Pour the heated cream and wine over the chocolate, let stand for one minute.
Stir until smooth. Pour over cooled cake, spreading with spatula if necessary. For a thinner ganache, increase heavy cream by 2 tablespoons.
Recipe by Laughing Over Spilled Milk at https://www.laughingoverspilledmilk.com/red-wine-chocolate-cake/