Make the Tart CrustIn a mixing bowl, combine the flour and sugar. Add the cold, cubed butter and rub it into the dry ingredients with your fingers or a pastry cutter until it resembles breadcrumbs. Add the egg yolk and 1 tbsp of cold water. Mix gently until the dough comes together. If needed, add another tablespoon of water.
Shape the dough into a disc, wrap it in plastic wrap, and refrigerate for 30 minutes.
Preheat your oven to 350°F (175°C).
Roll the chilled dough out on a lightly floured surface and carefully transfer it to your tart pan. Trim the edges and prick the base with a fork to prevent puffing.
Line the tart shell with parchment paper and fill it with baking weights. Bake for 15 minutes, remove the weights, and bake for another 5 minutes until golden. Let it cool completely.
Prepare the Pastry Cream FillingIn a saucepan, heat the milk over medium heat until it begins to steam (do not boil). In a separate bowl, whisk together egg yolks, sugar, and cornstarch until smooth.
Gradually pour the hot milk into the egg mixture, whisking constantly. Return the mixture to the saucepan.
Cook over medium heat, whisking constantly, until it thickens to a pudding-like consistency.
Remove from heat, stir in vanilla extract and butter, and let it cool completely. Cover with plastic wrap to prevent a skin from forming.
Assemble the TartSpread the cooled pastry cream evenly into the baked tart shell. Arrange your fresh fruits on top in a decorative pattern. Get creative with colors and shapes!
Warm the apricot jam and water in a microwave or small pan, then brush it lightly over the fruits to give them a glossy finish.
Chill and ServeRefrigerate the tart for at least an hour to allow the flavors to meld. Slice and serve chilled.