Custard Slice with Passion Fruit Icing

This recipe is based on Paul Hollywood’s Custard Slice from The Great Comic Relief Bake Off.
I love passion fruit so I have added it to the icing. Very messy to eat but awfully more-ish!

Ingredients
Rough puff pastry:
225 gms plain flour, plus extra for dusting
½ tsp salt
200g butter frozen
140-160 mls water
Crème pâtissière:
500ml milk
1vanilla pod, split down the middle and seeds scraped out
100gms caster sugar
4 free-range eggs, yolks only
40gms cornflour
40gms butter
Passion fruit Icing:
200gms icing sugar
1 passion fruit

Method
1.    In a large bowl mix the flour and salt together. Grate the butter and rub roughly into the flour mixture until it resembles fine breadcrumbs. Don’t worry if there are large lumps.
2.    Add the water a little at a time until the pastry just binds together (you may not need all the water).
3.    Tip the pastry out onto a floured work surface. Roll into a narrow rectangle about 2.5cm thick.
4.    With the pastry vertically in front of you fold the bottom third of the pastry up onto the middle third then the top third down onto the other thirds. This is called a turn.
5.    Wrap the pastry in cling film and place in the refrigerator to chill for 10 minutes
6.    Take out of fridge and with a rolling pin roll out again into a narrow rectangle and repeat the turn as before.
7.    Chill again and repeat the rolling and turning once more, so a total of three times. Wrap the pastry in cling film and return to the fridge to rest.
8.    While the pastry is resting, make the crème pâtissière. Pour the milk into a pan and add the split vanilla pod and its seeds. Bring the milk mixture to the boil, then remove from the heat.
9.    Whisk the sugar, egg yolks and cornflour together in a large bowl.
10.    Pour out a little of the hot milk onto the egg mixture, whisking continuously. Whisk in the rest of the hot milk until well-combined, then return to the pan.
11.    Cook the mixture over a gentle heat, stirring continuously, until the mixture becomes thick. It will just come to the boil.
12.    Remove from the heat and pass the mixture through a sieve into a clean bowl. Add the butter and stir until melted and thoroughly combined.
13.    Leave to cool, cover with cling film and then chill before using.

NOTE: My crème pâtissière did not set firmly enough, even in the fridge, so in desperation I used gelatine leaves to try to achieve a firm enough set to provide a firm filling in between the puff pastry layers, with limited success.
14.    Pre-heat the oven to 220 degrees C. Line two baking trays with baking parchment.
15.    Divide the pastry into two equal pieces and roll out both pieces to 20cm square and 5mm thick. Then place each pastry sheet onto the lined baking trays, and chill for 10-15 minutes.
16.    Bake the pastry sheets for 10-15 minutes or until golden-brown and crisp. Set aside to cool.
17.    While the pastry bakes, line a deep 23cm square baking tray with foil with plenty of extra foil at the sides. The extra foil allows you to lift out the assembled slices.
18.    Place one pastry sheet in bottom of the lined baking tray. (Reserve the prettiest piece for the top.)
19.    Spread the crème pâtissière evenly onto the pastry in the baking tray before placing other piece of pastry, on top. Refrigerate while making the icing.
20.    For the icing, sift the icing sugar into a bowl. Stir in the passionfruit pulper until thoroughly combined and set aside.
21.    Take the custard slice from the fridge and spread the icing over the top layer of pastry.
22.    Place the slice back into the fridge to set.
23.    Cut the finished vanilla slice into eight pieces.
24.    Using the foil carefully lift the portioned vanilla slices out of the tray and place onto a serving platter.