Step 1: Prepare the Tart Crust

1. In a mixing bowl, combine the flour, powdered sugar, and salt.
2. Add the cold, cubed butter and use a pastry cutter or your fingers to mix until the mixture resembles coarse crumbs.
3. Stir in the egg yolk until combined. If the dough is too crumbly, add ice water one tablespoon at a time until it comes together.
4. Shape the dough into a disk, wrap it in plastic wrap, and refrigerate for at least 30 minutes.

Step 2: Bake the Tart Shell

1. Preheat your oven to 350°F (175°C).
2. On a lightly floured surface, roll out the chilled dough to fit a 9-inch tart pan. Press the dough into the pan, trimming any excess.
3. Line the crust with parchment paper and fill with pie weights or dried beans. Bake for 15–20 minutes until lightly golden. Remove the weights and parchment, then bake for an additional 5 minutes to crisp the bottom. Let it cool completely.

Step 3: Make the Pastry Cream

1. In a saucepan, heat the milk and half of the sugar over medium heat until it begins to steam but does not boil.
2. In a separate bowl, whisk together the egg yolks, cornstarch, and remaining sugar until smooth.
3. Slowly pour the hot milk into the egg mixture while whisking constantly to temper the eggs.
4. Return the mixture to the saucepan and cook over medium heat, whisking constantly until it thickens and bubbles. Remove from heat and stir in the vanilla extract and butter.
5. Transfer the pastry cream to a bowl, cover with plastic wrap pressed directly onto the surface, and let it cool completely.

Step 4: Assemble the Tart

1. Once the tart shell and pastry cream are cool, pour the pastry cream into the tart shell and smooth the top.
2. Arrange the assorted fresh fruits on top of the pastry cream in a decorative pattern.

Step 5: Glaze (Optional)

1. If using, heat the apricot jam in a small saucepan until melted, then strain to remove any fruit pieces.
2. Brush the melted apricot jam over the fruit to give it a shiny finish.

Step 6: Serve

1. Refrigerate the tart for at least 1 hour before serving, then slice and enjoy.