The ultimate test of patisserie skills. Delicate flaky pastry layered with a silky crème diplomat and raspberry jam, topped off with a classic feathered fondant top.
For the rough puff pastry, mix the flour and salt together in a bowl. Rub in the chilled butter using your fingertips until the mixture resembles breadcrumbs. Gradually add enough cold water to form a dough (about 6 tablespoons).
On a lightly floured work surface, roll the dough out into a rectangle (approx. 15cm x 40cm).
Scatter half of the frozen butter over the bottom two-thirds of the dough. Fold down the top third and fold up the bottom third as if folding a letter.
Turn the folded dough by 90 degrees and roll it out into a rectangle again. Repeat the process of adding the remaining frozen butter and fold as before.
Wrap the dough in cling film and leave to rest in the fridge for 30 minutes before using.
For the crème pâtissière, pour the milk and cream into a pan. Add the vanilla paste and bring just to the boil, then take off the heat.
Whisk the egg yolks, caster sugar and cornflour together in a bowl. Pour the hot milk over the egg mixture whisking continuously. Return the mixture to the pan and cook over a low heat, stirring continuously until the cream thickens. Cook over a low heat for 2 - 3 minutes to cook out the flour.
Remove from the heat and pass through a sieve into a bowl, then beat in the butter until smooth. Pour out onto a shallow tray and cover the surface with cling film. Leave to cool then chill in the fridge until set.
Heat the oven to 220°C/200°C fan/425°F/Gas 7. Roll the pastry to a large rectangle measuring approx. 35cm x 45cm, about ½ cm thick. Place the pastry onto a baking sheet and chill for 10-15 minutes.
Place a baking sheet over the rolled-out pastry and bake for 20 - 30 minutes, until golden-brown and crisp. Remove from the oven, remove the top baking sheet and leave to cool.
For the icing, on a work surface lightly dusted with icing sugar, roll the white fondant into a 25 x 10 cm rectangle.
Break off small pieces of red and orange fondant and scatter them randomly over the white fondant. Using a rolling pin roll the coloured fondant into the white fondant to create a smooth, patterned effect. Cut out 4 rectangles of patterned fondant, each measuring 12cm x 5cm.
When the pastry has cooled, cut out 12 rectangles of pastry each measuring 12cm x 5cm.
Spoon the set crème pâtissière into a piping bag fitted with a ½ cm plain nozzle.
To assemble, set aside 4 pastry rectangles. Place a raspberry in the corner of one of the pastry rectangles. Pipe a blob of crème pâtissière next to it. Sit a raspberry next to it and continue piping crème pâtissière with alternating raspberries until the pastry is covered. Repeat this process on the remaining 7 pastry rectangles.
Sit the rectangles on top of each other so you have 4 double-layered pastries, topped with raspberries and crème pâtissière.
To decorate, brush sugar syrup over the remaining 4 pastry rectangles and stick the fondant rectangles to the pastry. Place on top of the raspberries and crème pâtissière and lightly brush with sugar syrup, to glaze the fondant icing.