Combine sugar syrup ingredients in a pan and bring to a boil while stirring.
Boil for 3 minutes, skim the surface, sieve, and cool the syrup completely.
Boil sugar and water for meringue until the syrup reaches 110°C.
Whisk egg whites to firm peaks in an electric mixer.
Remove sugar syrup from heat once it reaches 121°C.
Slowly pour hot syrup into whisking egg whites and continue beating for five minutes until tepid.
Blend passion fruit pulp and syrup until smooth, then strain.
Reserve 60ml of purée and boil the rest with milk powder and vanilla pod.
Whisk egg yolks and sugar until the mixture forms a ribbon.
Pour half the hot fruit mixture onto the yolks while whisking, then return everything to the pan.
Heat gently while stirring until thick enough to coat a spatula without boiling.
Stir in drained gelatine leaves and let cool slightly.
Discard vanilla pod and strain the custard through a conical sieve to cool.
Place the sponge flan base onto a tray.
Mix 50ml sugar syrup with reserved purée and brush over the sponge.
Press a 25cm flan ring into the sponge to create the base.
Fold in half the meringue, the liqueur, and the whipped cream into the lukewarm custard.
Fill the flan ring with mixture, smooth the surface, and freeze for several hours.
Preheat the oven to 200°C.
Beat butter, icing sugar, and honey for the tuiles until smooth.
Add egg whites one by one, then fold in the flour.
Spread a thin layer of tuile mixture through leaf-shaped stencils onto parchment paper.
Bake for 4 minutes until pale golden-brown.
Heat syrup and purée for the glaze, stir in gelatine, cool, and spread over the frozen delice.
Garnish with passion fruit seeds and upright tuiles before slicing.