Chocolate Sponge:
90g plain flour
15g cocoa powder
40g butter
4 eggs
100g caster sugar.
Heat oven to 180. Melt butter and keep warm. Crack eggs into mixing bowl, add sugar and suspend the bowl over but not touching, a pan of simmering water as you beat the egg and sugar mix (until it is thick but light) for about eight minutes. Take off heat and beat for another two minutes. Sift flour and cocoa over mixture and fold in carefully. Add melted butter once two thirds of the flour has been incorporated. Pour into springform tin and make 20-25 minutes. When cold, slice in half horizontally.
Cake Mousse Filling:
200g good dark chocolate, chopped small
140g pottle of sour cream
2Tbsp dark rum
300mL whipped cream (thick but not stiff)
Melt choc over hot water, remove from heat, add sour cream and run and stir till smooth. Add this to the whipped cream and mix . Spread between sponge cake layers. Chill for 6 hours or until mousse is firm.
Cake Icing:
150g dark choc
140 sour cream
Melt the choc, add sour cream and mix until smooth and shiny. Spead over top and sides of assembled cake.