Preheat oven to 180 degrees. Place the coffee, butter and cocoa in a small saucepan over a medium heat until the butter melts and the ingredients combine. Whisk until smooth. Break up the chocolate and stir into the mixture until it melts and the mixture is smooth. Let it cool for 10 minutes.
Place the sugar, baking powder, baking soda, salt and flour into a mixing bowl. Stir to combine. Pour the cooled chocolate mixture into the bowl with the dry ingredients and mix well to combine.
In a separate bowl, whisk together the eggs, vanilla and yoghurt until combined. Pour into the cake batter, stirring until combined well.
Grease a large cake tin (I have used a silicone bundt tin which works well for this recipe) and pour in the batter. Place in the oven for 50-55 minutes or until a skewer comes out clean when inserted. You can serve this on its own or with any sauce you desire.