01 - Combine flour, salt, and powdered sugar in a mixing bowl. Add cold butter and rub between fingertips until mixture resembles coarse meal. Add the egg and mix until dough forms a uniform mass. Shape into a ball, wrap in plastic, and refrigerate for 30 minutes.
02 - Preheat oven to 350°F. Roll out the dough and line a 9–10 inch tart pan. Prick the base with a fork, cover with parchment paper, and fill with pie weights. Bake for 20 minutes. Remove weights and paper, then bake an additional 10 minutes until lightly golden. Let cool completely.
03 - In a saucepan, heat milk and vanilla until just simmering. In a bowl, whisk egg yolks with sugar, then blend in cornstarch. Gradually add some hot milk, whisking constantly, then pour the mixture back into the saucepan. Cook over medium heat, whisking constantly, until thickened. Remove from heat and whisk in butter. Cover with plastic wrap directly touching the surface and chill until cool.
04 - Wash, hull, and slice the strawberries as desired.
05 - Spread chilled pastry cream evenly into the cooled crust. Arrange strawberries decoratively on top.
06 - Gently heat apricot jam with water. Brush over strawberries to give a glossy finish.
07 - Refrigerate the tart for at least 1 hour before serving.