Chocolate mud cake

Method

1. Preheat the oven to 160°C/fan140°C/gas 3. Grease and line a deep, 23cm round loose-bottomed cake tin, then set aside. Melt the chocolate, butter, espresso powder and milk in a heatproof bowl over a pan of barely simmering water until smooth. Remove from the heat and set aside.
2. Sift the flour and cocoa powder into a bowl, then add the caster sugar. Fold into the chocolate mixture along with the eggs, vanilla extract and soured cream.
3. Pour into the prepared cake tin and bake in the oven for 1 hour to 1 hour 10 minutes. The cake is ready when a skewer inserted into the centre comes out with some moist crumbs sticking to it but not any raw cake batter. Set aside to cool completely in the tin.
4. To make the ganache, melt the ingredients together, stirring occasionally, in a heatproof bowl set over a pan of simmering water. Set aside to cool at room temperature for 30 minutes. Remove the cake from the tin and leave to cool. Spread evenly all over with the ganache, swirling it into attractive patterns.