STEP 1: BAKE THE PUFF PASTRY FIRST
Preheat the oven to 200°C (400°F). Roll the puff pastry to approximately 3mm thick on a lightly floured surface. Transfer to a parchment-lined baking tray and dock all over with a fork. Place a second sheet of parchment on top, then set a second baking tray or wire rack on top and weigh it down with an oven-safe object. This forces the pastry to bake flat, creating the thin, crisp, shatteringly layered base that mille-feuille requires. Bake for 18–22 minutes until deep golden throughout. For extra caramelisation, dust with icing sugar and return to the oven for a further 2–3 minutes. Transfer to a wire rack and cool completely before cutting or assembling. Start this step first — the pastry has the longest cooling requirement of all the components.

STEP 2: POACH THE PEARS
While the pastry bakes, combine the Sauternes, caster sugar, cinnamon stick, star anise, vanilla pod (or extract), and lemon juice in a saucepan. Bring to a gentle simmer, stirring to dissolve the sugar. Add the pear wedges and place a cartouche (a circle of parchment cut to fit the pan) directly on the surface to keep the pears submerged and evenly poached. Poach at the gentlest simmer for 8–12 minutes until the pears are tender when pierced with a knife but still holding their shape. Remove from the heat and cool completely in the poaching liquid, then refrigerate or briefly freeze. The pears must be completely cold before assembly.

STEP 3: MAKE THE HAZELNUT PRALINE
Toast the hazelnuts in a dry frying pan over medium heat, stirring frequently, for 5–7 minutes until golden and fragrant. Line a baking tray with parchment or a silicone mat and spread the hazelnuts across it. In a clean, heavy-based saucepan, combine the granulated sugar and water. Cook over medium-high heat without stirring until the caramel reaches a deep amber colour — not pale gold. Immediately pour the hot caramel over the toasted hazelnuts. Sprinkle with flaky sea salt. Leave to cool and set until rock-hard, about 10–15 minutes at room temperature or 5 minutes in the freezer. Break into pieces and blitz in a food processor to a coarse, sandy powder with some small chunks remaining.

STEP 4: MAKE THE MASCARPONE PRALINE CREAM
In a large bowl, whisk the mascarpone until smooth. In a separate bowl, whip the cold double cream with the icing sugar and vanilla extract to soft peaks using an electric mixer — do not over-whip or the cream will become grainy. Gently fold the whipped cream into the mascarpone. Fold in approximately 50g of the blitzed praline. The cream should be thick, pipeable, and speckled with golden praline. Refrigerate until ready to assemble.

STEP 5: CONFIRM ALL COMPONENTS ARE COLD
Before assembly, confirm that the pastry is completely cool and crisp, the pears are cold and well drained (pat gently with kitchen paper to remove excess poaching liquid), and the praline cream is cold from the refrigerator. This is the single most important instruction in this recipe. Temperature discipline is the difference between a collapsed sandwich and a flawless layered tower: warm pears melt the cream on contact, destroying all structural integrity.

STEP 6: ASSEMBLE
Using a sharp serrated knife, carefully cut the cooled pastry sheet into neat rectangles approximately 10 x 5cm — you need three pieces per serving. For each mille-feuille: place one pastry rectangle on the plate. Pipe or spoon a generous layer of praline cream on top. Arrange cold pear wedges in a neat row over the cream, pressing very gently. Place a second pastry rectangle on top. Repeat with a further layer of cream and pears, then finish with a third pastry rectangle. The layers should be clearly visible from the side — alternating golden pastry, pale praline-speckled cream, and amber pear. Dust the top with icing sugar and drizzle any reduced poaching syrup around the plate.