1. Butter a 1.5-litre pudding basin or a heatproof glass bowl really well. Place a square of baking paper at the bottom of the bowl (this helps to unmold it later). Sift the cocoa powder together with the flour, bicarb and baking powder. Beat the butter and sugar together until fluffy, then gradually add the eggs, a little at a time, beating well after each addition. Fold in the sifted ingredients, alternating with the Guinness, until you have a smooth consistency. Next, fold in the walnuts, the dark chocolate and the prunes. Scrape the batter into the prepared basin.

2. Cut a square of foil approximately 4cm bigger than the top of the pudding basin and grease the underside with butter. Make a pleat in the middle of the square. Place it on top of the basin and tightly press around the edges, then tie with string to seal. Also, tie string up and over the pudding basin to make a handle.

3. Put the pudding in a large saucepan with a lid, then pour in enough boiling water to come one-third of the way up the side of the basin. Bring the water to a simmer, cover the pan and steam the pudding for 1 hour and 45 minutes, ensuring that the pan doesn’t boil dry. Remove the basin from the saucepan and leave to sit for 10 mins.

4. Meanwhile, make the chocolate and Guinness sauce. Put the chocolate in a heatproof bowl. Pour the cream, Guinness and dark brown sugar into a heavy-based saucepan and heat gently, stirring until the sugar has dissolved and the mixture is steaming hot but not boiling, then pour over the chocolate. Leave to sit for a minute or so. Stir from the inside out to avoid bubbles forming, until smooth.

5. To turn the pudding out, run a knife or a palette knife around the edge of the basin. Set a serving plate on top of the pudding, invert, give it a gentle shake, and it should slide right out. Peel off the square of baking paper. Pour some of the chocolate and Guinness sauce over the top. Serve with extra sauce and cream.