Special equipment: two pastry bags, one fitted with a large round tip, the other with a medium round tip
For the puff pastry: Preheat the oven to 350 degrees F.
Arrange the puff pastry on a baking sheet and dust with some confectioners' sugar. Bake until golden and caramelized, about 20 minutes. Remove from the baking sheet, cut out 8 circles, and set aside. Leave the oven on.
For the pate a choux: Heat the butter and 1 liter water in a saucepan over medium heat. Bring to boil, then remove from the heat and add the flour and salt, stirring until combined. Return to the heat for 1 minute, stirring. Transfer the mixture to the bowl of a stand mixer and let cool for 5 minutes. With the mixer on medium speed, add the eggs, one at a time, mixing until well combined. Transfer to a pastry bag fitted with a large round tip.
Pipe cream puffs onto two buttered baking sheets. Bake, switching and rotating the baking sheets halfway through, until cooked through, about 25 minutes. Set aside to cool.
For the sugar decoration: Add the isomalt crystals to a large Pyrex measuring cup; microwave in 30 second increments to melt. Set aside to cool slightly, then dip a whisk in the melted isomalt and fling slightly to make long strings of pulled sugar. Set aside.
For the custard: Wrap a rimmed baking sheet with plastic wrap and set aside. In a large pot, combine the milk, cream, vanilla bean and 250 grams of the sugar. Bring to a boil.
Meanwhile, whisk together the egg yolks and the remaining 40 grams sugar until light and fluffy.
Once the milk mixture boils, add the flour to the egg yolk mixture and then add a spoonful of the boiling milk.
Pour the egg yolk mixture into the boiling milk, whisking constantly; continue whisking until it returns to a boil. Immediately remove from the heat and pour onto the prepared baking sheet; fish out and discard the vanilla bean. Place in the freezer until fully cooled.
For the chantilly cream: Add the cream to the bowl of a stand mixer. Add some of the vanilla bean seeds, scraped from the pod, along with a spoonful of the confectioners' sugar. (Reserve the remainder of the vanilla bean for another use.) Beat to soft peaks.
Transfer a tenth of the whipped cream to a pastry bag fitted with a medium round tip. Poke the tip into the bottom of the cream puffs to fill them with cream.
Fold the custard into the remaining whipped cream to make diplomat cream.
To serve: Set a circle of puff pastry down on 4 plates, then add some diplomat cream to the center. Top with berries and then another circle of puff pastry. Arrange a cream puff next to the pastry.
Pipe some chantilly cream on top of each pastry, add more berries to the plates, and top with the isomalt pulled sugar. Serve immediately.
This recipe was created by a contestant during a cooking competition. It has not been tested for home use.