Preheat the oven to 180°C (Gas Mark 4) and grease a 25cm rectangular tin. Next, place the cocoa in a bowl and add the beer to create a paste.
Sift together the flour, bicarbonate of soda, and baking powder.
Cream the sugar and butter until soft, gradually adding the eggs and flour, and finally fold the cocoa paste into the mixture. Bake for about 30–35 minutes, then leave to cool.
Then, to prepare the 'lovely cream', whip the cream until soft peaks form, then combine the sugar, malt paste, and salt with it and mix.
To make the icing, melt the chocolate in a bowl over warm water; then, cream the butter and icing sugar until light and fluffy, adding the beer followed by the chocolate. Spread the mixture over the entire cake and finish with chocolate shavings. Serve in slices with the cream.