Make the Tart Crust: In a large bowl, whisk together the flour and salt. Cut in the cold butter using a pastry blender or your fingers until the mixture resembles coarse crumbs. Gradually add the ice water, one tablespoon at a time, mixing until the dough just comes together. Be careful not to overmix.

Chill the Dough: Form the dough into a disc, wrap it in plastic wrap, and refrigerate for at least 30 minutes.

Roll and Shape the Crust: Preheat your oven to 375°F (190°C). On a lightly floured surface, roll out the chilled dough to about 1/8-inch thickness. Use a cookie cutter or the rim of a glass to cut out circles slightly larger than your mini tart pans.

Press into Tart Pans: Gently press the dough circles into the mini tart pans. Trim any excess dough from the edges. Prick the bottoms of the crusts with a fork to prevent them from puffing up during baking.

Bake the Crusts: Line the tart crusts with parchment paper and fill with pie weights or dried beans. Bake for 15 minutes. Remove the parchment paper and weights and bake for another 5-7 minutes, or until the crusts are lightly golden brown. Let the crusts cool completely in the pans.

Make the Pastry Cream: In a medium saucepan, whisk together the milk, sugar, cornstarch, and salt. Cook over medium heat, whisking constantly, until the mixture begins to thicken.

Temper the Egg Yolks: In a separate bowl, whisk the egg yolks until light and frothy. Gradually whisk about 1/2 cup of the hot milk mixture into the egg yolks to temper them (this prevents them from scrambling).

Combine and Cook: Pour the tempered egg yolk mixture back into the saucepan with the remaining milk mixture. Continue to cook over medium heat, whisking constantly, until the pastry cream is very thick and smooth, about 1-2 minutes.

Finish the Pastry Cream: Remove the saucepan from the heat and stir in the butter and vanilla extract. Pour the pastry cream into a bowl, cover with plastic wrap (pressing the plastic wrap directly onto the surface of the cream to prevent a skin from forming), and refrigerate for at least 2 hours, or until completely chilled.

Assemble the Tarts: Once the tart crusts and pastry cream are completely cooled, spoon or pipe the pastry cream into the cooled tart shells.

Decorate with Fruit: Arrange the fresh fruit attractively on top of the pastry cream.

Glaze (Optional): If desired, warm the apricot jam or apple jelly in a small saucepan or in the microwave until melted. Brush the glaze over the fruit to give it a shiny finish.

Chill and Serve: Refrigerate the assembled Mini Fruit Tarts with Pastry Cream for at least 30 minutes before serving to allow the pastry cream to set completely.