1.Preheat oven to 180°C (160°C fan-forced). Grease a deep 22cm-round cake pan; line base and side with baking paper.
2.Blend cocoa powder with the hot water in a small bowl until smooth.
3.Stir the chocolate and butter in large heatproof bowl over a medium saucepan of simmering water until melted. Remove pan from heat; stir in cocoa mixture, sugar, ground almonds and egg yolks.
4.Beat egg whites in a clean small bowl with an electric mixer until soft peaks form; fold into chocolate mixture, in two batches. Pour mixture into pan.
5.Bake about 1 1/4 hours. Stand cake in pan for 15 minutes, before turning onto wire rack to cool.
6.Meanwhile, to make chocolate ganache, stir ingredients in a small saucepan over low heat until smooth.
7.Arrange the raspberries on the cake; pour the ganache over the cake to partially cover berries. Stand at room temperature until set.
Cake suitable to freeze. Chocolate ganache suitable to microwave.Note