Sachertorte

Equipment: Grease a 20cm x 5cm deep springform cake tin, and line the base and sides with baking paper.

Preheat the oven to 160°C regular bake.

Put the chocolate in a microwave-safe bowl and melt in the microwave in short bursts until just melted. Stir until smooth and cool until just warm.

In a stand mixer, beat the butter and ¼ cup of the sugar until pale and fluffy. Beat in the egg yolks one at a time, beating well after each addition. Add the melted chocolate and beat until well combined.

Slowly whisk the egg whites and salt until foamy, then increase the speed and gradually whisk in the remaining ½ cup sugar until the mixture is shiny and forms soft peaks when you lift up the whisk.

Beat a large spoonful of the egg whites into the chocolate mixture to loosen, then use a metal spoon to gently fold in the remaining whites in three lots.

Combine the flour, cocoa and the cornflour and sift over the chocolate mixture, add the ground almonds, then, using a large metal spoon, gently fold everything together, making sure there are no pockets of flour in the batter. Tip into the prepared tin and gently smooth the top.

Bake in the lower third of the oven for 30–35 minutes, or until a skewer inserted into the centre comes out clean. Cool for 30 minutes, then remove from the tin and cool completely on a cooling rack. The cake is best made one day ahead of filling and icing.

To assemble: Heat the jam in a small pot until hot then push it through a fine sieve into a bowl.

Halve the cake and put one half on a cooling rack set over a large plate. Spread the warm jam evenly over the top. Sandwich with the other half.

Put the chocolate and butter in a microwave-safe bowl and melt in short bursts in the microwave until just melted. Stir until smooth and the butter is fully incorporated. Cool to a spreading consistency.

Tip all the chocolate over the top of the cake then using a small offset spatula or knife, spread the chocolate evenly, letting it run down the sides then smoothing it to an even layer all the way around. Any excess chocolate will drip down onto the plate. Leave to set completely before cutting.

The cake will keep in an airtight container for two to three days.