Sacher Torte

Heat the oven to 160°C (140° fan) 325°F gas 3. Grease and flour a 22 cm|8 1/2" springform tin.

Melt the chocolate in a heatproof bowl over a pan of simmering (not boiling) water. Allow to cool slightly

Beat the butter and sugar in a mixing bowl until pale and fluffy, then beat in the chocolate.

Beat in the egg yolks, one at a time until blended.

Whisk the egg whites until stiff and fold gently into the mixture until incorporated.

Pour into the tin and bang the tin on the work surface to dispel any air pockets. Bake for 45-60 minutes until firm to the touch. Test by inserting a skewer into the centre -it should come out clean. Leave to cool in the tin then place on a wire rack to cool completely.

For the icing: melt the chocolate with 2 tablespoons water in a heatproof bowl over a pan of simmering (not boiling) water. Stir in the butter until smooth.

Put the remaining water and sugar in a pan and heat gently until the sugar has dissolved. Bring to a boil and boil for 3 minutes. Remove from the heat and allow to cool slightly.

Gradually pour the syrup into the melted chocolate, stirring until a thick icing consistency. You may not need all the sugar syrup. Allow to cool slightly then pour over the cake. Leave to set at room temperature.