Chocolate Guinness Cupcakes

1. Preheat the oven to 350ºF. Butter and put cupcake liners into molds.
2. Pour the Guinness into a large wide saucepan. Add the butter – in spoons or slices – and heat until the butter’s melted, at which time you should whisk in the cocoa and sugar. Beat the sour cream with the eggs and vanilla and then pour into the brown, buttery, beery pan and finally whisk in the flour and baking soda.
3. Pour the cake batter into the cupcake holders and bake for 20 minutes or until a toothpick inserted comes out clean. Leave to cool completely in the tin on a cooling rack, as it is quite a damp cake.
4. When the cupcakes have cooled completely, make the icing. Lightly whip the cream cheese until smooth, sieve over the confectioner’s sugar and then beat them both together. Or do this in a processor, putting the unsieved confectioner’s sugar in first and blitz to remove lumps before adding the cheese.
5. Add the cream and beat again until it makes a spreadable consistency. Ice the top of the black cupcakes so that they resemble the frothy top of the famous pint.