Crème brûlée cheesecake

Instructions

1. Preheat the oven to 150°C. Grease and line the base and sides of a 20cm-diameter round springform cake tin. When lining the sides of the tin, cut the baking paper 6cm higher than the height of the tin, taking care to overlap the paper where the two ends of the sheet join, so there is no gap. (The cheesecake will rise during baking, and lining the tin above its top edge prevents the cheesecake filling from overflowing – imagine the layer of baking paper acting as an extension of the baking tin.)
2. For the base, place the ginger biscuits in a blender and blitz until a fine crumb forms. Add the melted butter and pulse once or twice more until the mixture is incorporated. Tip the mixture into the prepared cake tin and press it very firmly and evenly into the base, smoothing it out with the back of a spoon.
3. Bake the base in the preheated oven, 15 minutes, before cooling at room temperature, 10 minutes. Refrigerate, 30 minutes, while preparing the cheesecake filling.
4. Place the castor sugar, vanilla paste and essence, salt, egg yolks and the whole egg either in the bowl of a stand mixer or a large bowl if using a hand-held electric mixer. Beat until fluffy, about 3 minutes. Add the cream cheese and beat, scraping down the sides of the bowl if required, until just smooth. Add the fresh cream and beat until just combined. Boil the kettle.
5. Line the outside of the chilled tin with a large piece of heavy duty foil, so as to cover the bottom and sides in one large piece. Then line the outside of the cake tin with a second sheet of heavy duty foil to create a watertight, double layer, and place the tin in a deep roasting tray. (The method to the madness is to make the cake tin watertight, to protect your cheesecake from the water as it cooks in the water bath.)
6. Pour the cream cheese mixture into the biscuit base and pour boiling water into the roasting tray around the cake tin. The water should come about halfway up the sides of the tin; don’t overfill, as it will be difficult to pick up the roasting tray if it's too heavy.
7. Bake in the preheated oven, 1 hour and 40 minutes. (The cake should be set, but have a slight wobble.) Switch off the oven, but leave the cake in the oven with the door ajar, 1 hour. Remove the cake tin from the water bath after the 1 hour has passed and chill in the fridge to firm up, 4 hours or overnight.
8. Remove the cheesecake from the fridge, 10 minutes before serving. Carefully remove it from the tin and peel off the baking paper.
9. Place the cheesecake on a round serving platter or cake stand and sprinkle generously with castor sugar, then caramelise the sugar with a kitchen blowtorch to create the crème brûlée topping. If you're not serving the entire cheesecake at once, you could cut slices and then caramelise the tops of the individual slices, or caramelise only the part of the cake you think you will need. (Stored in the fridge, the caramelised topping will not retain its crunch and will become sticky. Therefore, it's best to caramelise just before serving.) To slice, tap the top of the cake to shatter the caramel in slices, then dip a sharp knife in boiling water and wipe it dry to help with slicing. Decorate with fresh raspberries and mint leaves.