Combine flour and sugar in a mixing bowl.
Rub cold butter into the flour mixture until coarse crumbs form.
Add egg yolk and ice water, mixing until dough forms.
Shape dough into a disk, wrap, and chill for 30 minutes.
Preheat oven to 375°F (190°C).
Roll out chilled dough and press into tart pan. Prick base with a fork.
Bake tart shell for 15–18 minutes until lightly golden. Cool completely.
Heat milk in saucepan until hot but not boiling.
Whisk sugar, cornstarch, and egg yolks until smooth.
Temper egg mixture by gradually whisking in hot milk.
Return mixture to saucepan and cook over medium heat, stirring until thickened.
Remove from heat; stir in butter, rosewater, and vanilla. Cover and cool.
Spread cooled rosewater pastry cream evenly inside the tart shell.
Arrange fresh raspberries decoratively atop the cream.
Refrigerate tart for 1 hour to set before serving.