Chocolate mousse with coffee granita

300g dark chocolate, chopped
150g unsalted butter, at room temperature
6 eggs, seperated
50ml white rum
40g caster sugar
100 ml cream

Coffee granita:
300ml hot espresso coffee
90g caster sugar
1 tbsp liquid glucose

1. Melt dark chocolate in a bowl over a pan of simmering water. Stir in butter and egg yolks, then add rum.
2. Whisk eggwhites in a bowl and add sugar. Whisk cream in another bowl, then fold eggwhite mixture and cream through chocolate. Pour into bowl and cover. Allow to set for 1-2 hours or until firm.
3. To make coffee granita, combine coffee, sugar and glucose until sugar dissolves. Pour coffee mixture into a clean tempered glass or ceramic vessel, then put in freezer. After 2 hours, stir with a fork to break up the ice crystals. Return to feezer and leave overnight before serving.
4. To serve, put a scoop of mousse in a glass, then top with a generous scoop of granita and a coffee bean.