Baking white chocolate in a low oven caramelises the sugars to create ‘blonde’ chocolate, which has a distinctive, nutty sweetness. This, in turn, brings a whole new level of flavour to these cheesecakes.
Make the biscuit base. Heat the oven to 190°C/170°C fan/375°F/Gas 5. Tip the flour, salt, oats and caster sugar into a large bowl. Using your fingertips, rub 15g of the butter into the flour mixture until it resembles breadcrumbs. Stir in the honey, then sprinkle the crumb mixture evenly over the lined baking tray and bake for 8-10 minutes, until golden. Remove from the oven and leave the biscuit crumbs to cool on the tray. Turn the oven down to 170°C/150°C fan/335°F/Gas 3
Make the blackcurrant jelly. While the crumbs are baking, soak the gelatine leaves in a bowl of cold water for 5 minutes to soften. Place the blackcurrants in a mini food processor and blitz to a purée.
Pass the blackcurrant purée through a fine-mesh, nylon sieve into a small pan, then add the sugar and 3 tablespoons of water. Place the pan on a medium heat and bring the blackcurrant purée to the boil, then remove from the heat.
Drain the gelatine leaves, squeezing out any excess water, then add them to the hot purée. Stir to melt the gelatine, then pour the blackcurrant mixture into the silicone-lined tray in an even layer. Leave to cool, then chill for 30 minutes, until set.
Finish the cheesecake base. Blitz the cooled biscuit into fine crumbs in a food processor.
Melt the remaining 35g of butter in a small pan, remove the pan from the heat and stir in the biscuit crumbs until coated and combined. Divide the mixture equally between the 6 holes of the silicone mould or 6 chef's rings, pressing it down with the base of a glass or the end of a rolling pin to an even layer. Chill in the freezer for 10 minutes to firm up.
Make the caramelised white chocolate. Tip the white chocolate into a heatproof bowl and microwave it on high for 30 seconds, then stir it with a spatula. Repeat the 30 seconds in the microwave between 15 and 20 times, stirring after every 30 seconds, until the chocolate is golden brown in colour - take care as the bowl will get very hot; use oven gloves each time you remove it from the microwave to stir. During the process, the chocolate becomes lumpy and chalky, but keep stirring it until it's smooth again. Once it's ready, leave it to cool while you prepare the rest of the filling.
Make the filling. Beat the cream cheese in a stand mixer fitted with the beater, on medium speed until smooth. Add the egg and egg yolk and continue to beat until smooth again. Add the caramelised chocolate, cornflour and cream, then beat on low speed until well mixed.
Pour equal amounts of the filling over each biscuit base and bake for 25-30 minutes, until the cheesecakes start to brown, but still have a slight wobble in the centre. Remove them from the oven, leave them to cool, then chill until firm.
Make the chocolate decoration. First, temper the white chocolate by melting 75g of the white chocolate in a heatproof bowl set over a pan of gently simmering water. Heat it until it reaches 40°C (104°F) on the cooking thermometer, stirring occasionally so it melts evenly. Remove the bowl from the pan and leave it to stand for 10 minutes, then stir in the remaining chocolate. Stir continuously until the chocolate cools to 25°C (77°F), then place the bowl back over the pan of simmering water and stir until the chocolate reaches 27°C (81°F).
Lay the sheet of acetate on your work surface and, using a palette knife, spread the tempered white chocolate on top in an even layer, about 3mm thick. Leave for 10 minutes, until almost set, then cut the chocolate into triangles of about 9 x 9 x 4cm. Leave the chocolate triangles to set completely, then carefully peel them off the acetate.
Assemble the cheesecakes. Once chilled, pop the cheesecakes out of the moulds and place each one on a serving plate. Using the 7cm round cutter, cut 6 rounds from the set blackcurrant jelly and place one on top of each cheesecake.
Decorate the cheesecakes. Whip the double cream, vanilla and icing sugar together to medium peaks, then spoon the sweetened cream into the small piping bag fitted with a small ribbon nozzle. Pipe a wavy line down the middle of each cheesecake, then position a white chocolate triangle at one end. Finish with blackcurrants and blackcurrant leaves, if using.