01 - Pulse flour, powdered sugar, and salt in a food processor until combined. Add cold butter and pulse until mixture resembles coarse crumbs. Add egg yolk and pulse again. Gradually add ice water, 1 tablespoon at a time, just until dough comes together. Flatten into a disk, wrap in plastic, and refrigerate for at least 1 hour.
02 - Preheat oven to 350°F.
03 - On a lightly floured surface, roll out the dough to fit a 9-inch tart pan. Press into the pan and trim excess dough. Prick the base with a fork.
04 - Line the crust with parchment paper and fill with pie weights or dried beans. Bake for 15 minutes, remove the weights and parchment, then bake for another 8–10 minutes until golden brown. Let cool completely.
05 - In a medium saucepan, heat milk and vanilla bean (both seeds and pod) over medium heat until just simmering. Remove and discard the vanilla pod.
06 - In a bowl, whisk egg yolks, sugar, cornstarch, and salt until pale and smooth.
07 - Slowly pour the hot milk into the egg mixture, whisking constantly to prevent curdling. Return the mixture to the saucepan and cook over medium heat, whisking constantly, until thickened and bubbling (about 2–3 minutes). Remove from heat and stir in butter until smooth and glossy.
08 - Transfer pastry cream to a clean bowl, cover with plastic wrap directly on the surface to prevent a skin from forming, and refrigerate until cold (at least 1 hour).
09 - Spread the chilled pastry cream evenly into the cooled tart shell. Top with fresh berries or seasonal fruit if desired. Dust with powdered sugar just before serving if preferred.