• 125 g (4½ oz) caster (superfine) sugar
• 100 g (3½ oz) dark chocolate (70% cocoa)
• 4 large free-range egg yolks
• 2 tablespoons unsweetened cocoa powder
• 60 ml (2 fl oz/¼ cup) Kahlua
• 300 g (10½ oz) sour cream
• 12 pitted prunes, thinly sliced
• 60 ml (2 fl oz/¼ cup) hot and strong coffee
• 115 g (4 oz/1 cup) walnut halves
• 3 tablespoons icing (confectioners’) sugar

Line a 7 x 22 cm (2¾ x 8½ inch) loaf (bar) tin with baking paper, allowing 5 cm (2 inches) of paper to overhang the two long sides.

Put the sugar and 125 ml (4 fl oz/½ cup) water in a saucepan. Bring to the boil, stirring until the sugar has dissolved. Boil briskly for 3 minutes, then remove from the heat. Break the chocolate into pieces and add to the hot sugar syrup, stirring until smooth.

Using an electric mixer, whisk the egg yolks until pale, then add the cocoa and whisk until combined. Slowly add the hot chocolate sauce, beating until the mixture has cooled. Stir in 1 tablespoon of the Kahlua, then beat in the sour cream. Spoon the mixture into the prepared tin and freeze overnight.

Put the prunes in a small bowl and pour the hot coffee and remaining Kahlua over the prunes. Cover and set aside until ready to serve.

Put the walnuts in a non-stick frying pan and sprinkle over the icing sugar. Cook over medium heat until the sugar melts and the walnuts begin to caramelise. Remove from the pan.

To serve, turn the parfait out onto a clean board and cut into six slices. Serve with the prunes and caramelised walnuts.