Roasted Plum and Pistachio Custard Pastries

Prepare the rough puff pastry: The night before, wrap 120g of butter in foil and freeze until solid. In a large bowl, combine 300g of plain flour, icing sugar, and a pinch of salt. Rub the 50g of cold chopped butter into the flour until it looks like fine breadcrumbs. Stir in 7-9 tbsp of ice-cold water until the dough just comes together. Roll the dough into a rectangle on a floured surface. Using a coarse grater, grate half of the frozen butter over the bottom two-thirds of the pastry. Fold the top third down and the bottom third up (like a letter). Rotate 90 degrees and repeat the process with the remaining frozen butter. Wrap and chill for at least 30 minutes.

Make the pistachio paste: Place 75g of the pistachios in a heatproof bowl and cover with boiling water. Let them soak for 5 minutes, then drain. Transfer the nuts to a food processor and blend for 5-10 minutes, scraping down the sides as needed, until a smooth paste forms. Set aside.

Prepare the pistachio custard: Simmer the milk and double cream in a small pan over medium heat, then remove. In a separate bowl, whisk the egg yolks, caster sugar, 15g of plain flour, and cornflour together. Gradually whisk the warm milk mixture into the egg mixture. Return the mixture to a clean pan over low heat and cook, stirring constantly, until the custard thickens. Simmer for 2 more minutes, add a pinch of sea salt, and let cool. Once cooled, blend the custard with the prepared pistachio paste in a food processor until smooth.