Pre-heat the oven to 175°C (350°F) and grease/line two 8 inch cake tins.
Melt the dark chocolate and then add the hot brewed coffee. Stir to combine, and set to one side.
In a large bowl, or using a food processor (which I did), beat the butter and sugars together until light and fluffy. Add the eggs one at a time. Lastly, add the vanilla extract.
Pour the chocolate/coffee mixture into the butter/sugar and give it a quick burst just until everything is evenly distributed.
In a separate bowl, combine the cocoa, flour, and baking soda.
Mix the cream and milk together in another bowl. While the processor is running, slowly add one third of the dry ingredients to the butter/chocolate mixture, and then one third of the milk/cream. Repeat until you've added everything (don't over mix - just continue until everything is combined).
Divide the batter fairly evenly between the two pans and bake for around 20-25 minutes. The cakes are ready when the tops are fairly springy and an inserted skewer comes out clean.
Remove from the oven and let the cakes sit in the pans for ten minutes or so, before turning out onto a wire rack to cool completely.