265g plain chocolate (39 per cent cocoa solids), broken into pieces
6 large eggs, 5 of them separated
215g caster sugar
150g ground almonds
For the topping and icing
About 4 tablespoons apricot jam
150g plain chocolate (39 per cent cocoa solids), broken into pieces
150ml pouring double cream
25g white chocolate
Use a deep, round, loose-based 23cm cake tin
A superb rich, very densely textured chocolate cake, named after the Sacher hotel in Vienna. Ground almonds replace the flour, which means the cake keeps well.
Preheat the oven to 180C. Grease the cake tin and line the base with non-stick baking parchment. Put the chocolate into a bowl placed over a pan of hot water. Place the pan over a low heat until the chocolate has melted, stirring occasionally. Allow to cool a little.
Whisk the 5 egg whites in a large mixing bowl until stiff but not dry. In a separate large mixing bowl, use a hand-held electric mixer to whisk together the 5 egg yolks, whole egg and sugar until thick and pale. The mixture should be thick enough to leave a trail on the surface when the whisk is lifted from the bowl.
Whisk the ground almonds, melted chocolate and 1 tablespoon of the whisked egg whites into the egg yolk mixture. Carefully fold in the remaining egg whites using a large metal spoon or a straight-edged plastic spatula. Turn the mixture into the tin.
Bake for 40-45 minutes, until the crust that forms on the top is firm and the cake has begun to shrink away from the side of the tin. Allow the cake to cool in the tin for about 10 minutes before loosening it around the edge with a small palette knife. Turn the cake upside down onto a wire rack covered with a tea towel. Peel off the parchment and leave to cool completely.
Gently heat the apricot jam in a small pan and then brush it evenly over the top and sides of the cake.
To make the icing, put the chocolate into a bowl with the double cream and melt slowly over a pan of hot water. Stir occasionally until smooth and glossy. Allow the icing to cool and thicken slightly, then pour it onto the centre of the cake. Spread it gently over the top and down the sides with a palette knife and leave to set. To finish, melt the white chocolate slowly in a bowl over a pan of hot water. Spoon into a small paper icing bag or polythene bag, snip off the corner and pipe "Sacher" across the cake and leave to set.
Taken from 'My Kitchen Table: 100 Cakes and Bakes' by Mary Berry (Ebury, £7.99).