01 - Combine the all-purpose flour, powdered sugar, and salt in a large mixing bowl. Add the cold, diced butter and rub together until the mixture resembles coarse crumbs. Incorporate the egg and mix until a smooth dough forms. Shape into a disk, wrap in plastic, and chill for 30 minutes.
02 - Preheat the oven to 350°F. Roll out the chilled dough on a floured surface and fit into a 9 to 10-inch tart pan. Prick the base with a fork, line with parchment paper, and fill with pie weights. Bake for 20 minutes, then remove the weights and parchment. Bake for an additional 10 minutes, or until lightly golden. Let cool completely.
03 - Heat the whole milk with the vanilla bean (split and scraped) or vanilla extract in a saucepan just to a simmer. In a separate bowl, whisk the egg yolks with sugar until pale. Add the cornstarch and whisk until smooth. Gradually pour some hot milk into the eggs, whisking constantly, then return the mixture to the saucepan. Cook over medium heat, stirring continuously, until thickened. Remove from the heat and stir in the butter. Cover directly with plastic wrap and cool completely.
04 - Wash, hull, and slice the strawberries as desired for topping.
05 - Spread cooled pastry cream evenly in the cooled tart shell. Arrange the prepared strawberries on top in an attractive pattern.
06 - Warm the apricot jam with water, then brush gently over the strawberries for a glossy finish. Refrigerate the tart for at least 1 hour before serving.