Make the crust:
In a food processor, combine flour, powdered sugar, and salt. Add butter and pulse until mixture is crumbly. Add egg yolk and cold water. Pulse until dough starts to come together.
Press dough into a 9-inch tart pan with a removable bottom. Chill for 30 minutes.

Bake the crust:
Preheat oven to 375°F (190°C). Prick the bottom of the crust with a fork, line with parchment and fill with pie weights or dried beans.
Bake for 15 minutes, then remove weights and bake for another 10–12 minutes until golden. Let cool completely.

Make the pastry cream:
In a medium saucepan, whisk together milk, sugar, and cornstarch. In a separate bowl, whisk egg yolks.
Slowly whisk some hot milk into yolks, then pour everything back into the saucepan.
Cook over medium heat, whisking constantly, until thickened (about 5–7 minutes).
Remove from heat, stir in butter and vanilla. Let cool slightly, then refrigerate until cold.

Assemble the tart:
Spread chilled pastry cream into the cooled crust. Arrange fresh fruit over the top in a decorative pattern.

Optional glaze:
Warm apricot jam with water and brush over fruit for a shiny finish. Chill tart until ready to serve.