20 minutes, plus chilling
250g unsalted butter, chopped into cubes, plus extra for greasing
250ml chocolate stout or Guinness
100g plain chocolate (70% cocoa solids), broken into pieces
35g cocoa powder
400g golden caster sugar
142g natural yogurt
1 tablespoon vanilla extract
275g plain flour
2½ teaspoons bicarbonate
For the icing
1 x 75cl bottle of champagne
500g cream cheese
200g icing sugar
250ml double cream
Preheat the oven to 180°C/Gas Mark 4. Butter and line the base and sides of a 24cm diameter, deep, round, loose-bottomed tin.
Melt the butter together with the Guinness in a large saucepan, then add the chocolate. Once the chocolate has melted, add the cocoa powder and sugar and mix well.
In a separate bowl, whisk together the eggs, yogurt and vanilla extract, then add to the chocolate mixture. Whisk in the flour and bicarbonate of soda and whisk well until you have a smooth batter. Pour this mixture into the tin and bake for 45 minutes. If a knife comes out clean, it’s done. Leave to cool in the tin.
Meanwhile, to make the icing, pour the champagne into a saucepan, bring to the boil and reduce it down until you only have 2 tablespoons left. Leave to cool completely before adding it into the cream cheese.
In a large bowl, lightly whip the cream cheese together with the icing sugar and champagne reduction until smooth.
In a separate bowl, whip the cream until it thickens but still retains its shape. Fold the cream into the cream cheese mixture until it is smooth and a spreadable consistency. I like to chill it for an hour or two while the cake is cooking and cooling.
Remove the cake from the tin. If the top is still a little crusty and domed, level it with a knife (save these bits for decoration), then cut the cake horizontally into 3 even slices. Lay the base slice on to a cake plate or stand. Spread over about 4-5 tablespoons of the icing,
sandwich the next layer on and then repeat with another 4-5 tablespoons of icing and place the final layer on top.
Take half the remaining icing and ice the sides of the cake, levelling it out to be smooth (the layer should be about 3mm thick). Pour the remaining icing on top and level it out flat. I make black crumbs by blitzing the excess cake in a food processor and sprinkle them neatly around the edge of the cake.