Creating the Berry Fruit Tart with Vanilla Custard can be straightforward when you follow these easy steps:

For the Tart Crust:

1. Preheat Oven: Preheat your oven to 350°F (175°C).
2. Combine Dry Ingredients: In a mixing bowl, whisk together the flour, sugar, and salt.
3. Cut in Butter: Add the cubed cold butter to the flour mixture. Using a pastry cutter or your fingers, work the butter into the dry ingredients until the mixture resembles coarse crumbs.
4. Add Egg Yolk: Stir in the egg yolk until combined.
5. Add Ice Water: Gradually add the ice water, one tablespoon at a time, until the dough holds together. Avoid overmixing.
6. Chill the Dough: Wrap the dough in plastic wrap and refrigerate for at least 30 minutes.
7. Roll and Shape: Roll out the chilled dough on a lightly floured surface to fit a 9-inch tart pan. Press the dough into the pan and trim the edges.
8. Blind Bake: Place parchment paper over the crust and fill with pie weights. Bake for 15 minutes. Remove the parchment and weights, and bake for an additional 10-15 minutes until golden.
9. Cool: Allow the tart crust to cool completely.

For the Vanilla Custard:

10. Heat Milk: In a saucepan, heat the milk and sugar over medium heat until almost boiling. Remove from heat.
11. Whisk Egg Yolks and Cornstarch: In a separate bowl, whisk together the egg yolks and cornstarch until smooth.
12. Temper the Mixture: Gradually pour the heated milk into the egg yolk mixture, whisking constantly to prevent curdling.
13. Cook Custard: Pour the mixture back into the saucepan and return to medium heat. Cook, stirring constantly until it thickens, about 5-7 minutes. Do not let it boil.
14. Finish Custard: Remove from heat, stir in the vanilla extract and butter until smooth and well combined.
15. Cool Custard: Pour the custard into a bowl, cover with plastic wrap (pressing it directly onto the surface to prevent skin from forming), and refrigerate until chilled.

Assemble the Tart:

16. Fill the Tart Shell: Once the custard is chilled, pour it into the cooled tart shell and smooth the top with a spatula.
17. Add Berries: Arrange the fresh berries over the custard in whatever design you prefer.
18. Chill Again: Refrigerate the assembled tart for at least 1 hour before serving.