For the best results, you will need to prepare this cake the day before you plan to serve it and for the ice cream layers to freeze and set perfectly. If you can find small Paradise pears when they are in season, then poach these to top the finished cake – failing that, use regular pears, which will be no less delicious.
Heat the oven to 200°C/180°C fan/400°F/Gas 6.
Make the honey and hazelnut ice-cream mixture. Melt the butter in a small pan over a low heat. Remove from the heat and add the hazelnuts, 35g of the honey and the salt. Mix to combine, then tip onto the lined baking tray. Roast for 8 minutes, until golden, then leave to cool.
In a large bowl whisk together the milk, cream, remaining 125g of honey and the vanilla. Cover and chill.
Make the butterscotch and pecan ice-cream mixture. Melt the brown sugar and butter together in a medium pan over a medium heat. When the mixture is bubbling, add the whipping cream and stir until smooth.
Remove from the heat and add the milk, double cream, caster sugar, salt and vanilla and whisk until thoroughly combined. Cover and chill.
Make the chocolate tuille. Draw two sets of parallel lines, each 30 x 13cm, on the baking paper that lines one of the baking sheets. In a stand mixer fitted with the beater, cream the butter and icing sugar together until smooth and pale. Add the egg whites a little at a time, mixing well between each addition. Sift the flour and cocoa into the bowl and mix again until just combined.
Using a palette knife, spread the paste evenly onto the baking paper keeping the mixture within the drawn lines and to a thickness of about 2mm. Run the decorating comb through the paste to from a neat pattern and wipe the comb clean in between each swipe. Freeze for about 30 minutes, until solid.
Meanwhile, make the joconde sponge. Combine the ground almonds, icing sugar and flour in a stand mixer fitted with the beater. Add the whole eggs and yellow food colouring and whisk for about 5 minutes, until light and aerated. Gradually add the melted butter, mixing until combined.
In another bowl whisk the egg whites until they hold soft peaks. Add the caster sugar and continue to whisk until stiff but not dry. Carefully fold the egg whites into the cake mixture and, working quickly with an offset palette knife, spread the joconde mixture evenly on top of the frozen chocolate tuille. Bake for 12 minutes, until golden.
Make the chocolate joconde. Using a cake tin or plate as a guide, draw three 18cm-diameter circles on the baking paper lining the remaining baking sheets, leaving space between each one.
Combine the ground almonds, icing sugar, flour and cocoa in the bowl of a stand mixer fitted with the beater. Add the whole eggs and beat for about 5 minutes until light and aerated. Slowly add the melted butter and continue to mix until combined.
In another bowl whisk the egg whites until they hold soft peaks. Add the caster sugar and continue to whisk until stiff but not dry. Carefully fold the egg whites into the cake mixture and, using an offset palette knife, spread the mixture inside the circles that you have drawn on the baking paper, to create discs. Bake for 12–13 minutes, until springy.
Position the strip of acetate around the inside of the lined springform tin. Trim the edges and sides of the striped joconde cake into two 12cm-high strips and place them into the tin upright against the acetate and with the stripes facing outwards. Using the 18cm cake tin or a plate as a guide, trim all three of the chocolate joconde cakes onto neat discs and place one into the tin, inside the striped joconde to line the base. Place in the freezer while you churn the ice cream.
Churn the honey and hazelnut ice cream in the ice-cream machine according to the manufacturer’s instructions and add the honey-toasted hazelnuts for the last 3 minutes to mix through.
Spoon the ice cream into the cake lined tin, spread level and place another cake layer on top, gently pressing together. Freeze again while you churn the pecan ice cream, adding the chopped pecans to the ice cream at the last minute.
Spoon the pecan ice cream into the tin, top with the third cake layer and gently press together. Freeze again for at least 6 hours, but preferably overnight.
Meanwhile poach the pears. Pour 750ml water into a medium pan. Add the caster sugar, cinnamon sticks, halved vanilla pod, blackberries and lemon juice and bring slowly to the boil. Simmer gently for 20 minutes.
Use a vegetable peeler to peel the pears and add them to the pan. Poach them for about 20 minutes, depending on the ripeness and size of the pears, until tender (they should yield to the point of a knife). Remove from the heat and leave to cool in the blackberry syrup.
Prepare the blackberry mousse. Soak the gelatine leaves in a bowl of cold water for 5 minutes, until soft and floppy. Combine the blackberries, caster sugar and lemon juice in a pan and cook over a low–medium heat, until the berries are very soft and juicy. Simmer for 1 minute, then push the berries through a sieve and discard the pips. Drain the gelatine, squeeze out the excess water, and add it to the hot blackberry purée. Stir to melt the gelatine and leave the mixture to cool to room temperature.
Whip the cream until it holds soft peaks. Fold it into the cold blackberry purée and spoon this on top of the ice-cream cake. Spread it level and return it to the freezer for another hour.
To serve, dust the top of the blackberry mousse with cocoa and carefully remove the cake from the tin. Peel off the acetate and place the cake on a serving plate. Top with the drained blackberry poached pears and decorate with fresh blackberries, edible flowers and gold leaf.