Make the base first
200 grams plain, sweet biscuits * [I like to use Malt or Digestive biscuits]
100 grams butter
50 grams brown sugar
Crush the biscuits. Melt the butter and brown sugar together and combine well with the crushed biscuits. Press the mixture onto the bottom of a foil-lined springform pan and chill.
Next, make the cheesy bit
250 grams cream cheese
100 grams caster sugar
100 grams chocolate [milk, dark or white]
2 egg whites
300 ml pouring cream
Soften the cream cheese a little and beat well. Beat in half the sugar. Melt the chocolate over a bowl of hot water or in a microwave. Allow the chocolate to cool slightly, them combine with the cream cheese mixture. Beat the egg whites till stiff, then fold in the remaining caster sugar. Whip the cream, and fold the egg white mixture through carefully using a metal spoon. Combine the chocolate and cream mixtures well, and pile on top of the base. Decorate with extra cream and/or grated chocolate. Refrigerate until ready to eat.
* Terminology clarification: here in Australia, a biscuit is what people in the USA might call a cookie or a cracker. (What someone in the USA would call a biscuit, we would call a scone or a muffin. Confused yet?) Anyway, if you're making this recipe in the USA, graham crackers are probably a good approximation. You may also need a metric to imperial measurement conversion facility.