Chocolate mousse with coffee granita

500g good-quality dark chocolate, chopped
150g unsalted butter, at room temp
6 eggs, separated
2.5 Tbsp white rum
40g caster sugar
250ml pouring cream, lightly whipped
Thickened cream to serve

COFFEE GRANITA
380ml hot espresso coffee
90g caster sugar
1 tbsp liquid glucose

1. To make granita, put coffee, sugar and glucose in a small bowl and stir until sugar is dissolved. Pour mix into a shallow plastic container and freeze for 4 hours. Once frozen, scratch surface with a fork to make granita.
2. Line and oven tray with baking paper. Melt 200g of the chocolate in a heatproof bowl over a pan of barely simmering water. Set aside to cool until choc thickens slightly.
3. Spoon chocolate into a piping bag. Pipe 10 spirals onto prepared tray. Set aside to cool at room temp for 1 hour then refrigerate for 15 mins to firm completely.
4. To make mousse, melt remaining choc in a large heatproof bowl over a pan of barely simmering water. Add butter, yolk and rum, and stir until smooth.
5. Whisk eggwhites and sugar until soft peaks form, then fold through choc mixture. Fold in whipped cream and stir gently until smooth. Cover and refrigerate until set firm.
6. Serve mousse in chilled glasses, topped with coffee granita, a dollop fo cream and a chocolate swirl.