For the dough: Put the butter, dark chocolate and sugar in a small saucepan over very low heat (or over a water bath), just until melted.
Set aside and let cool a bit. Add the egg and mix well, then add the flour and mix. At last, stir in the red wine.
Bake in a buttered mold (12 cm Ø ) at 175° for about 30 – 40 minutes.
For the glaze: Melt the butter and chocolate over a waterbath. Remove from heat, whisk in the icing sugar and salt, then the warmed wine. Let cool in the fridge. The colder it gets, the thicker it will be.
If your cake is not even, cut of the little mound, then cut it in two layers.
With a brush, soak both of them generously with red wine. The cake will be moist und juicy and the flavors of wine and chocolate have a perfect balance.
Spread some glaze on the first layer, place the second layer on top and also glaze it.