Preheat the oven to 180°C (350°F/Gas 4).
Lightly grease a 25 cm (10 inch) springform tin with butter, then dust with flour, shaking out the excess.
Place all the ingredients except the icing sugar in a food processor and blend until smooth. Pour into the prepared tin and bake for 30 minutes, or until just set.
Carefully remove the cheesecake from the oven, sprinkle the icing sugar over the top and bake for another 10 minutes. Remove the cheesecake from the oven and, using a kitchen blowtorch, brown the top until it is very dark. Alternatively, brown the cheesecake under a very hot grill (broiler).
Allow to cool before serving.