300g Oreo biscuits
150g unsalted butter
300g good-quality dark chocolate, chopped
100ml espresso coffee
3 eggs, separated
2/3 cup (150g) caster sugar
1/2 cup (75g) plain flour
300ml thickened cream
1 tbsp Irish whisky
Preheat oven to 160°C. Grease and line the base of a 22cm spring-form cake pan with baking paper.
Place biscuits in a food processor and whiz until fine crumbs. Melt 70g butter, then add to the crushed biscuits and pulse to combine. Press the biscuit mixture into the base of the pan, then chill for 15 minutes.
Place the chocolate and remaining 80g butter in a saucepan over medium-low heat and stir until melted. Add the espresso and stir to combine. Remove from heat and cool for 10 minutes.
Place egg whites in the bowl of an electric mixer. Whisk with a pinch of salt until soft peaks form, then gradually add the sugar and whisk until stiff and glossy.
Gently beat yolks together in a large bowl, then stir in the cooled chocolate mixture. Stir in the flour, then fold in one-third of the egg white to loosen. Fold in remaining egg white until combined. Pour into prepared pan and bake for 40-45 minutes until a skewer inserted in the center comes out clean with just a few moist crumbs. Cool cake slightly.
Whisk the cream to soft peaks, fold in the whisky and serve with the cake.