- Beat the butter and sugar together until fluffy. Stir in the egg yolks and vanilla. Stir in the flour and salt until the dough comes together. Shape the dough into a disc, wrap in plastic wrap and chill for at least 2 hours, until firm.
- Preheat the oven to 350°F. Knead the pastry dough on a lightly floured surface to soften enough that it can be easily rolled. Dust the pastry a little and roll it out to just over 11-inches in diameter and just under a ¼-inch thick. Line a 9-inch removable-bottom fluted tart pan and trim the edges. Chill the pastry for 20 minutes in the fridge, or 10 minutes in the freezer.
- Dock the bottom of the pastry shell with a fork and bake it for 16 to 20 minutes, until just the edges are golden brown and the centre of the shell is dry looking. Cool completely before filling.
- Keep the baked tart shell in its pan. Melt the white chocolate in a bowl placed over a pot of barely simmering water, stirring until melted. Brush the bottom and sides of the cooled tart shell to coat and chill the shell while preparing the pastry cream.
- Heat the milk in a heavy-bottomed saucepot until just below a simmer. Whisk the eggs, sugar and cornstarch in a small bowl. Whisk half of the hot milk into the egg mixture, then pour this entire mixture back into the pot with the remaining milk. Whisk the custard constantly over medium heat until it thickens and just begins to bubble, about 3 to 4 minutes. Strain the custard into a bowl, stir in the vanilla and butter until melted and then cover the bowl with plastic wrap so that the wrap directly covers the surface of the custard. Cool the custard to room temperature, then chill it for at least 2 hours.
- To assemble the tart, spoon the custard into the tart shell and spread it evenly. Top the custard with the fresh fruit, creating an appealing design. Melt the apple jelly over low heat, and then brush it over the fruit. Chill the tart until you are ready to serve.
The tart can be stored chilled for up to a day.