Soak the prunes in the alcohol for 30 minutes

Preheat the oven to 180 degrees. Grease a 20cm springform tin with butter and line the base with greased greaseproof paper

Beat the egg yolks with the caster sugar on high speed until thick and creamy

Place the chocolate and 2 tablespoons of water in an ovenproof bowl, sitting on the rim of a small pan of simmering water. Stir the melting chocolate and water together until smooth. Slowly incorporate the butter, a few pieces at a time, to form a smooth, shiny liquid

Pour the melted chocolate mixture over the whisked egg yolks, and gently fold together using a large metal spoon

Sift the ground almonds and cornflour over the chocolate mixture, add the soaked prunes and alcohol, and gently fold through

In a clean, dry bowl, whisk the eggs whites until they form firm peaks that do not wobble when the bowl is shaken. Stir a large spoonful into the chocolate mixture, then gently fold in the remaining egg whites

Pour the mixture into the prepared tin, and bake in the centre of the oven for 35-40 minutes until the centre of the torte is just set. Leave to get cool in the tin on a wire rack

Run a sharp knife around the edge of the torte, remove the tin and lining paper, and transfer the torte to a serving dish

Serve in narrow slices with double cream or a dollop of creme fraiche on the side.