Step 1

Preheat the oven to 180°C/fan160°C/gas Grease and line a 23cm loose-bottomed cake tin.

Step 2

Beat the butter with the sugar until pale and fluffy – this may take around 5 minutes or so. Gradually beat in the melted chocolate until smooth, then beat in the eggs one at a time.

Step 3

Gradually whisk in the Guinness. You will have a smooth batter at this point. Sift together the flour, cocoa powder, baking powder and bicarbonate of soda, then fold carefully into the chocolate mixture.

Step 4

Pour into the tin and bake for 35-40 minutes until a skewer comes out clean. Leave to cool in the tin, then turn out onto a cake plate.

Step 5

For the icing, beat the cream cheese, icing sugar and vanilla extract together until smooth, then mix in the soured cream and melted chocolate. Spread evenly over the cake and serve.