For the sugar syrup, place all the ingredients into a pan and slowly bring to the boil, stirring occasionally with a wooden spoon.
Boil for about 2-3 minutes, skimming the surface if necessary. Pass the syrup through a fine sieve and leave until completely cold before using.
For the Italian meringue, place the sugar and water into a pan and slowly bring to the boil until the syrup reaches 110C/230F on a sugar thermometer.
At this stage, whisk the egg whites in the bowl of an electric mixer until firm peaks form when the whisk is removed.
As soon as the sugar reaches 121C/250F, remove the pan from the heat.
Immediately resume whisking the egg whites - with the beater at its lowest speed, pour in the melted sugar, in a thin, steady stream. CAUTION: Ensure the syrup is clear of the beaters, as it could be splashed on your hands. Continue beating for about five minutes, until the meringue is tepid.
For the passionfruit delice, blend the passion fruit pulp and the sugar syrup in a food processor until smooth. Strain the mixture through a fine sieve.
Reserve four tablespoons of the passion fruit purée and place the rest into a pan. Add the milk powder and vanilla pod and bring to the boil.
Whisk the egg yolks and sugar in a bowl until the mixture forms a ribbon when the whisk is removed.
Pour half of the passion fruit mixture onto the egg mixture, whisking continuously, then pour this custard mixture back into the pan.
Heat gently, stirring continuously with a spatula, until the custard is thick enough to coat the spatula. Do not allow it to boil.
Remove the pan from the heat and stir in the drained gelatine leaves. Set aside to cool slightly.
Discard the vanilla pod, and then pass the custard through a conical sieve into a bowl and leave to cool, stirring occasionally to prevent a skin forming.
For the base of the delice, place the sponge flan base onto a board or baking tray.
Mix together 50ml/2fl oz of the cold sugar syrup and the reserved passion fruit purée and brush this mixture over the sponge.
Place a 25cm/10in flan ring (6cm/2½in deep) onto the sponge and press down to cut out a circle, leaving the sponge as the base of the flan ring.
When the custard is lukewarm, gently fold in half of the Italian meringue (the remaining meringue can be used in another recipe). Stir in the passion fruit liqueur, and then fold in the whipped double cream. (You must now assemble the dessert immediately, before the gelatine causes the mixture to set.)
Fill the flan ring with the passion fruit custard mixture, leaving a small gap at the top, and carefully smooth the surface with a palette knife. Transfer to the freezer and chill for several hours.
Preheat the oven to 200C/400F/Gas 6.
For the tuiles, beat the butter, icing sugar and honey in a bowl until smooth.
Gradually beat in the egg whites, one at a time, until well combined. Then carefully fold in the flour using a metal spoon.
Take a piece of silicone or plastic and cut out long thin leaf shapes to create a stencil. Line a baking tray with baking parchment then place the stencil onto the tray. Using a palette knife, spread a thin layer of the tuile mixture into the cut-out part of the stencil. Carefully remove the template and repeat with the remaining mixture.
Place the tray into the oven and bake for 3-4 minutes, or until pale golden-brown.
For the glaze, place the sugar syrup and the passion fruit pulp into a pan and heat gently, then remove from the heat, stir in the drained gelatine and set aside to cool. Once cool, remove the delice from the freezer and spread the glaze over the top of the passion fruit filling. Transfer to the fridge to chill again before serving.
To serve, remove the flan ring by heating the outside of the ring with a blowtorch for a few seconds, then slide the ring upwards, rotating it slightly. Spoon the remaining passion fruit seeds into the centre of the delice. Place the tuiles upright around the edge of the delice to form a ring. Cut into slices to serve.