01 - In a food processor, pulse flour, powdered sugar, and salt to combine. Add cold butter and pulse until the mixture resembles coarse crumbs. Add egg yolk and pulse again. Add ice water, 1 tablespoon at a time, just until dough comes together. Flatten into a disk, wrap in plastic, and chill 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. Prick the base with a fork.
04 - Line the crust with parchment 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. Let cool completely.
05 - In a medium saucepan, heat milk and vanilla bean (both seeds and pod) over medium heat until just simmering. Remove 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.
08 - Return mixture to the saucepan and cook over medium heat, whisking constantly, until thick and bubbling (about 2–3 minutes). Remove from heat and stir in butter until smooth.
09 - Transfer pastry cream to a bowl, cover with plastic wrap directly on the surface, and chill until cold (at least 1 hour).
10 - Spread the chilled pastry cream evenly into the cooled tart shell. Top with fresh berries or fruit, if desired. Dust with powdered sugar before serving, if desired.