Sift flour and powdered sugar into a large bowl.

Rub in cold, chopped butter using fingertips until mixture resembles breadcrumbs.

Add egg yolk and mix to form a firm but pliable dough.

Knead lightly.

Wrap in plastic wrap and refrigerate for 30 minutes.

Preheat the oven to 375°F (190°C).

Roll out pastry between 2 sheets of parchment paper to 1/8-inch thickness.

Press into a 9-inch tart pan with removable bottom.

Trim edges.

Refrigerate for 15 minutes.

Line pastry with parchment paper and fill with dried beans.

Bake for 10 minutes.

Remove paper and beans.

Bake for 10-15 minutes until golden.

Cool completely.

For the pastry cream, heat milk in a medium saucepan with the vanilla bean until almost boiling.

Set aside to infuse vanilla flavor.

Beat egg yolks and granulated sugar in a medium bowl with an electric mixer on medium speed until thick and pale.

Beat in cornstarch.

Remove vanilla bean from warm milk.

Whisk in egg mixture.

Cook, stirring, on medium heat until custard boils and thickens.

Place plastic wrap directly on surface of custard to prevent a skin from forming.

Cool completely.

Spoon pastry cream into tart shell.

Refrigerate until chilled.

Top with strawberries, raspberries, and blueberries.

Dust with powdered sugar just before serving.