01 - Combine flour, sugar, and salt in a bowl. Cut in cold butter until mixture resembles coarse crumbs. Add egg yolk and 2 tablespoons cold water, mixing until dough forms, adding more water if necessary. Shape into a disk, wrap, and refrigerate for 30 minutes.
02 - Preheat oven to 375°F. Roll chilled dough on a floured surface to fit a 9-inch tart pan. Press dough into pan, trim edges, and prick base with fork. Line with parchment and fill with pie weights. Bake for 20 minutes, remove weights and parchment, then bake an additional 10 to 15 minutes until golden. Cool completely.
03 - Heat milk in a saucepan until steaming. Whisk egg yolks, sugar, and cornstarch in a bowl until smooth. Gradually whisk hot milk into egg mixture. Return to saucepan and cook over medium heat, stirring constantly until thickened, about 3 minutes. Remove from heat, stir in butter and vanilla extract. Transfer to a bowl, cover surface with plastic wrap, and cool completely.
04 - Spread cooled pastry cream evenly within the chilled pastry shell. Arrange pear, apple, grapes, pomegranate, kiwi, and orange slices artfully on top.
05 - Warm apricot jam with water in a small saucepan until smooth and melted. Optionally strain and then brush gently over the arranged fruit to glaze.
06 - Refrigerate tart for at least 1 hour prior to serving to allow flavors to meld and glaze to set.