1. Grease a deep 23cm round cake pan, line base with paper; grease paper. Melt butter and chocolate in heatproof bowl over hot water; cool to room temperature.
2. Beat egg yolks, essences and sugar in small bowl with electric mixer until pale and thick. Transfer mixture to large bowl, stir in rum and chocolate mixture, then almonds and sifted flour and cocoa

3. Beat egg whites in small bowl until soft peaks form, gradually add extra sugar, beat until dissolved between each addition, fold into chocolate mixture. Spread into prepared pan, bake in moderate oven (180C) for about 30 minutes. Stand 5 minutes before turning onto wire rack, leave cake upside down.

Glaze

1. Combine corn syrup, butter .3 and water in saucepan, stir over heat until mixture comes to the boil; remove from heat. Stir in chocolate, stir until smooth. Stand until bubbles subside, strain, spoon warm glaze over cold cake. Stand at room temperature until set.