Passion fruit vanilla slice is a very popular australian school canteen pastry, this recipe brings back many sticky memories.
Makes 4 large squares.
Preheat the oven to 200C / 390F.
Cut the puff pastry into thirds, lay on a tray on top of baking paper. Lay another sheet of baking paper on top and then another tray on top to stop it puffing up too much in the oven.
Prepare a square baking pan for the custard filling. Ideally the pan should be about the size of two pieces of the puff pastry (or a little larger). Line the inside with baking paper and then grease the inside.
Bake the pastry on a tray for 15 minutes or until golden brown. Leave the pastry to cool.
While the puff pastry is baking add the sugar, corn flour, custard powder, passion fruit juice, agar and a cup of milk to a saucepan over a medium heat. Whisk constantly to stop lumps from forming. When it is very thick pour it into the lined pan and leave it to set hard.
While the custard is setting make the icing by mixing the icing sugar, margarine and passion fruit together and set aside. If it is too thin add more icing sugar.
After about half an hour, when the custard has set remove it from the pan and slice it in half. If required trim it so that it fits to a piece of pastry exactly. On a platter place a piece of pastry, half the custard, another piece of pastry, custard and the pastry.
Spread the icing over the top layer and refrigerate for two hours.