Step 1: Soak the chopped prunes in port for several hours.

Step 2: Preheat the oven to 220°C. Roast the walnuts on a baking tray for 6–8 minutes, then rub off the skins with a clean tea towel and coarsely chop the nuts.

Step 3: Heat the chocolate gently with the cream in the top of a double saucepan over boiling water. (If you don’t have a double boiler, use a heatproof bowl that fits snugly over a pan of boiling water.) Remove from the heat before all the chocolate has melted. Stir continuously off the heat to finish melting the chocolate, then cool.

Step 4: Fold the drained soaked prunes and chopped nuts into the cooled chocolate mixture, then roll into balls and dust with cocoa.